{"id":4507,"date":"2026-05-28T05:25:09","date_gmt":"2026-05-28T04:25:09","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/cp-4-hydrolysis-of-halogenoalkanes\/"},"modified":"2026-06-10T10:28:45","modified_gmt":"2026-06-10T09:28:45","slug":"cp-4-hydrolysis-of-halogenoalkanes","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-4-hydrolysis-of-halogenoalkanes\/","title":{"rendered":"CP 4 &#8211; Hydrolysis of Halogenoalkanes"},"content":{"rendered":"\n<section class=\"ols-cp-page ols-cp4-halogenoalkanes-page\" id=\"ols-cp4-page\">\n  <style>\n    .ols-cp-page {\n      --navy: #1C244B;\n      --blue: #2563eb;\n      --blue-2: #0f4fa8;\n      --soft-blue: #eef4ff;\n      --soft-green: #f0f7f1;\n      --soft-red: #fff7f7;\n      --soft-purple: #f7f0ff;\n      --soft-gold: #fff8e8;\n      --soft-cyan: #effaff;\n      --green: #3f8f46;\n      --red: #d94b2b;\n      --gold: #c9973a;\n      --purple: #7a3e9d;\n      --grey-text: #667085;\n      --body-text: #1f2937;\n      --border: rgba(28, 36, 75, 0.14);\n      --shadow: 0 18px 45px rgba(28, 36, 75, 0.10);\n      --inner-shadow: 0 10px 26px rgba(28, 36, 75, 0.08);\n      font-family: Poppins, Arial, sans-serif;\n      color: var(--navy);\n      background: #ffffff;\n    }\n\n    .ols-cp-page * { box-sizing: border-box; }\n\n    .ols-cp-sidebar-shortcode {\n      max-width: 1180px;\n      margin: 0 auto;\n      padding: 24px 20px 0;\n    }\n\n    .ols-cp-shell {\n      display: block;\n      max-width: 1180px;\n      margin: 0 auto;\n      padding: 24px 20px 60px;\n    }\n\n    .ols-cp-main { min-width: 0; max-width: none; }\n\n    .ols-breadcrumbs {\n      display: flex;\n      flex-wrap: wrap;\n      gap: 8px;\n      margin: 10px 0 22px;\n      font-size: 15px;\n      color: var(--grey-text);\n    }\n\n    .ols-breadcrumbs a,\n    .ols-breadcrumbs span {\n      color: var(--grey-text);\n      text-decoration: none;\n      font-weight: 600;\n    }\n\n    .ols-breadcrumbs a:hover {\n      color: var(--blue);\n      text-decoration: underline;\n      text-underline-offset: 3px;\n    }\n\n    .ols-title-card,\n    .ols-note-card,\n    .ols-related-card,\n    .ols-faq-card {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 28px;\n      box-shadow: var(--shadow);\n      padding: 34px;\n      margin-bottom: 24px;\n      overflow: visible;\n    }\n\n    .ols-title-card {\n      background: radial-gradient(circle at top right, rgba(37, 99, 235, 0.13), transparent 34%), linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n    }\n\n    .ols-title-card h1 {\n      margin: 0 0 18px;\n      font-size: clamp(34px, 5vw, 58px);\n      line-height: 1.06;\n      font-weight: 850;\n      letter-spacing: -0.04em;\n      color: #111827;\n    }\n\n    .ols-page-intro {\n      font-size: 19px;\n      line-height: 1.7;\n      font-weight: 300;\n      color: var(--body-text);\n      margin: 0 0 22px;\n    }\n\n    .ols-badges {\n      display: flex;\n      flex-wrap: wrap;\n      gap: 12px;\n      margin-bottom: 22px;\n    }\n\n    .ols-badge {\n      display: inline-flex;\n      align-items: center;\n      padding: 9px 14px;\n      border-radius: 999px;\n      background: #ffffff;\n      border: 1px solid var(--border);\n      font-size: 15px;\n      font-weight: 650;\n      color: var(--navy);\n    }\n\n\n    .ols-author {\n      display: flex;\n      align-items: center;\n      gap: 20px;\n      padding: 28px;\n      border-radius: 28px;\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n      border: 1px solid rgba(28, 36, 75, 0.12);\n      box-shadow: 0 18px 45px rgba(28, 36, 75, 0.10);\n      margin-top: 22px;\n    }\n\n    .ols-author-avatar-img {\n      width: 92px;\n      height: 92px;\n      border-radius: 50%;\n      object-fit: cover;\n      object-position: center;\n      flex-shrink: 0;\n      border: 4px solid #ffffff;\n      box-shadow:\n        0 14px 32px rgba(28, 36, 75, 0.18),\n        0 0 0 1px rgba(28, 36, 75, 0.10);\n      transition:\n        transform 0.25s ease,\n        box-shadow 0.25s ease;\n    }\n\n    .ols-author:hover .ols-author-avatar-img {\n      transform: scale(1.04);\n      box-shadow:\n        0 20px 42px rgba(28, 36, 75, 0.22),\n        0 0 0 1px rgba(28, 36, 75, 0.10);\n    }\n\n    .ols-author-content { min-width: 0; }\n\n    .ols-author-title {\n      margin: 0 0 4px;\n      font-size: clamp(24px, 3vw, 34px);\n      line-height: 1.15;\n      font-weight: 700;\n      color: var(--navy);\n      letter-spacing: -0.03em;\n    }\n\n    .ols-author-description {\n      margin: 0;\n      font-size: 17px;\n      line-height: 1.7;\n      font-weight: 300;\n      color: var(--grey-text);\n    }\n\n    .ols-linkedin-pill {\n      display: inline-flex;\n      align-items: center;\n      justify-content: center;\n      gap: 10px;\n      margin-top: 16px;\n      padding: 11px 18px;\n      border-radius: 999px;\n      background: linear-gradient(135deg, #0A66C2, #004182);\n      color: #ffffff;\n      text-decoration: none;\n      font-size: 14px;\n      line-height: 1;\n      font-weight: 700;\n      letter-spacing: 0.01em;\n      box-shadow: 0 10px 22px rgba(10, 102, 194, 0.24);\n      position: relative;\n      overflow: hidden;\n      transition:\n        transform 0.22s ease,\n        box-shadow 0.22s ease;\n    }\n\n    .ols-linkedin-pill::before {\n      content: \"\";\n      position: absolute;\n      top: 0;\n      left: -120%;\n      width: 100%;\n      height: 100%;\n      background: linear-gradient(\n        120deg,\n        rgba(255,255,255,0) 0%,\n        rgba(255,255,255,0.28) 50%,\n        rgba(255,255,255,0) 100%\n      );\n      transition: left 0.7s ease;\n    }\n\n    .ols-linkedin-pill:hover {\n      transform: translateY(-3px) scale(1.03);\n      box-shadow:\n        0 16px 34px rgba(10, 102, 194, 0.34),\n        0 0 0 6px rgba(10, 102, 194, 0.10);\n      color: #ffffff;\n    }\n\n    .ols-linkedin-pill:hover::before { left: 120%; }\n\n    .ols-linkedin-icon {\n      width: 18px;\n      height: 18px;\n      display: block;\n      flex-shrink: 0;\n    }\n\n\n    .ols-note-card.soft { background: linear-gradient(135deg, #ffffff 0%, var(--soft-red) 100%); }\n    .ols-note-card.green { background: linear-gradient(135deg, #ffffff 0%, var(--soft-green) 100%); }\n    .ols-note-card.purple { background: linear-gradient(135deg, #ffffff 0%, var(--soft-purple) 100%); }\n    .ols-note-card.gold { background: linear-gradient(135deg, #ffffff 0%, var(--soft-gold) 100%); }\n    .ols-note-card.cyan { background: linear-gradient(135deg, #ffffff 0%, var(--soft-cyan) 100%); }\n\n    .ols-note-title {\n      display: flex;\n      align-items: center;\n      gap: 14px;\n      margin-bottom: 20px;\n    }\n\n    .ols-note-icon {\n      width: 52px;\n      height: 52px;\n      border-radius: 16px;\n      background: var(--navy);\n      color: #ffffff;\n      display: grid;\n      place-items: center;\n      font-size: 24px;\n      font-weight: 800;\n      flex-shrink: 0;\n    }\n\n    .ols-note-title h2,\n    .ols-related-card h2,\n    .ols-faq-card h2 {\n      margin: 0;\n      font-size: clamp(27px, 3.4vw, 42px);\n      line-height: 1.15;\n      font-weight: 850;\n      color: #111827;\n      letter-spacing: -0.03em;\n    }\n\n    .ols-note-card p,\n    .ols-note-card li,\n    .ols-related-card p,\n    .ols-faq-card p,\n    .ols-faq-card li {\n      font-size: clamp(15px, 1.25vw, 17px);\n      line-height: 1.7;\n      font-weight: 300;\n      color: var(--body-text);\n    }\n\n    .ols-note-card strong,\n    .ols-related-card strong,\n    .ols-faq-card strong {\n      font-weight: 750;\n      color: var(--navy);\n    }\n\n    .ols-note-card ul,\n    .ols-note-card ol {\n      margin: 0;\n      padding-left: 22px;\n    }\n\n    .ols-key-box {\n      margin-top: 20px;\n      background: #ffffff;\n      border: 1px solid rgba(37, 99, 235, 0.20);\n      border-left: 6px solid var(--blue);\n      border-radius: 18px;\n      padding: 18px 20px;\n    }\n\n    .ols-key-box p {\n      margin: 0;\n      font-weight: 400;\n      color: var(--navy);\n    }\n\n    .ols-process-grid,\n    .ols-apparatus-grid,\n    .ols-error-grid,\n    .ols-qa-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 14px;\n      margin-top: 22px;\n    }\n\n    .ols-apparatus-grid,\n    .ols-error-grid,\n    .ols-qa-grid {\n      grid-template-columns: repeat(2, minmax(0, 1fr));\n      gap: 16px;\n    }\n\n    .ols-process-step,\n    .ols-apparatus-card,\n    .ols-error-card,\n    .ols-qa-card,\n    .ols-rate-card {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 20px;\n      padding: 18px;\n      box-shadow: var(--inner-shadow);\n      position: relative;\n    }\n\n    .ols-process-step span {\n      display: inline-grid;\n      place-items: center;\n      width: 34px;\n      height: 34px;\n      border-radius: 50%;\n      background: var(--blue);\n      color: #ffffff;\n      font-weight: 800;\n      margin-bottom: 12px;\n    }\n\n    .ols-process-step h3,\n    .ols-apparatus-card h3,\n    .ols-error-card h3,\n    .ols-qa-card h3,\n    .ols-rate-card h3 {\n      margin: 0 0 8px;\n      font-size: 18px;\n      line-height: 1.25;\n      color: var(--navy);\n    }\n\n    .ols-process-step p,\n    .ols-apparatus-card p,\n    .ols-error-card p,\n    .ols-qa-card p,\n    .ols-rate-card p {\n      margin: 0;\n      font-size: 14px;\n      line-height: 1.58;\n      color: var(--body-text);\n    }\n\n\n    .ols-figure-card {\n      margin: 26px 0 4px;\n      border: 1px solid var(--border);\n      border-radius: 26px;\n      overflow: visible;\n      background: #ffffff;\n      box-shadow: var(--inner-shadow);\n      position: relative;\n      z-index: 1;\n    }\n\n    .ols-figure-image {\n      width: 100%;\n      min-height: 300px;\n      display: flex;\n      align-items: center;\n      justify-content: center;\n      background: #ffffff;\n      padding: 20px;\n      border-radius: 26px 26px 0 0;\n      overflow: visible;\n      position: relative;\n      cursor: zoom-in;\n    }\n\n    .ols-figure-image::after {\n      content: \"Click to enlarge\";\n      position: absolute;\n      right: 14px;\n      bottom: 14px;\n      z-index: 3;\n      padding: 8px 12px;\n      border-radius: 999px;\n      background: rgba(28, 36, 75, 0.88);\n      color: #ffffff;\n      font-size: 12px;\n      line-height: 1;\n      font-weight: 800;\n      opacity: 0;\n      transform: translateY(6px);\n      transition: opacity 0.22s ease, transform 0.22s ease;\n      pointer-events: none;\n    }\n\n    .ols-figure-image:hover::after {\n      opacity: 1;\n      transform: translateY(0);\n    }\n\n    .ols-figure-image img {\n      max-width: 100%;\n      height: auto;\n      display: block;\n      cursor: zoom-in;\n      transition: transform 0.32s ease, box-shadow 0.32s ease, filter 0.32s ease;\n      transform-origin: center center;\n      will-change: transform;\n      position: relative;\n      z-index: 2;\n    }\n\n    .ols-figure-image.contain img { width: auto; max-width: 100%; }\n\n    .ols-figure-image.structure-classification-small {\n      min-height: 0;\n      padding: 22px;\n    }\n\n    .ols-figure-image.structure-classification-small img {\n      width: auto;\n      max-width: 620px;\n      max-height: 520px;\n      margin: 0 auto;\n    }\n\n    @media (hover: hover) and (pointer: fine) {\n      .ols-figure-card .ols-figure-image:hover img {\n        transform: scale(1.5);\n        box-shadow: 0 30px 80px rgba(28, 36, 75, 0.28);\n        filter: saturate(1.05) contrast(1.03);\n      }\n\n      .ols-figure-card:hover { z-index: 50; }\n    }\n\n    .ols-figure-caption {\n      padding: 22px 26px 24px;\n      background: linear-gradient(135deg, #ffffff, #f8fbff);\n      border-top: 1px solid var(--border);\n      border-radius: 0 0 26px 26px;\n    }\n\n    .ols-figure-caption h3 {\n      margin: 0 0 8px;\n      color: var(--navy);\n      font-size: clamp(21px, 2vw, 28px);\n      line-height: 1.25;\n      font-weight: 800;\n      font-style: italic;\n    }\n\n    .ols-figure-caption p {\n      margin: 0;\n      color: #5f6b85;\n      font-size: clamp(15px, 1.2vw, 17px);\n      line-height: 1.6;\n      font-weight: 300;\n      font-style: italic;\n    }\n\n    .ols-cp4-lightbox {\n      position: fixed;\n      inset: 0;\n      background: rgba(8, 13, 31, 0.88);\n      backdrop-filter: blur(6px);\n      z-index: 999999;\n      display: none;\n      align-items: center;\n      justify-content: center;\n      padding: 24px;\n    }\n\n    .ols-cp4-lightbox.is-open { display: flex; }\n\n    .ols-cp4-lightbox img {\n      max-width: min(96vw, 1500px);\n      max-height: 92vh;\n      width: auto;\n      height: auto;\n      display: block;\n      border-radius: 18px;\n      box-shadow: 0 30px 90px rgba(0, 0, 0, 0.38);\n      background: #ffffff;\n    }\n\n    .ols-cp4-lightbox button {\n      position: absolute;\n      top: 18px;\n      right: 18px;\n      width: 44px;\n      height: 44px;\n      border-radius: 999px;\n      border: 1px solid rgba(255, 255, 255, 0.35);\n      background: #ffffff;\n      color: var(--navy);\n      font-family: Poppins, Arial, sans-serif;\n      font-size: 26px;\n      line-height: 1;\n      cursor: pointer;\n      font-weight: 800;\n      box-shadow: 0 14px 36px rgba(0, 0, 0, 0.24);\n    }\n\n    .ols-cp4-lightbox button:hover { background: var(--soft-blue); }\n\n    .ols-cp4-lightbox p {\n      position: absolute;\n      left: 28px;\n      right: 84px;\n      bottom: 16px;\n      margin: 0;\n      color: #ffffff;\n      font-size: 14px;\n      line-height: 1.4;\n    }\n\n\n    .ols-table-wrap {\n      overflow-x: auto;\n      border-radius: 22px;\n      border: 1px solid var(--border);\n      background: #ffffff;\n      margin-top: 18px;\n    }\n\n    .ols-table {\n      width: 100%;\n      border-collapse: collapse;\n      min-width: 680px;\n    }\n\n    .ols-table th {\n      background: var(--navy);\n      color: #ffffff;\n      padding: 15px 16px;\n      text-align: left;\n      font-size: 15px;\n      font-weight: 700;\n      vertical-align: top;\n    }\n\n    .ols-table td {\n      padding: 15px 16px;\n      border-bottom: 1px solid var(--border);\n      font-size: 15px;\n      line-height: 1.55;\n      color: var(--body-text);\n      vertical-align: top;\n    }\n\n    .ols-table tr:last-child td { border-bottom: none; }\n\n    .ols-highlight-fast { background: var(--soft-green); font-weight: 650; }\n    .ols-highlight-slow { background: var(--soft-red); font-weight: 650; }\n\n    .ols-equation {\n      display: block;\n      width: fit-content;\n      max-width: 100%;\n      overflow-x: auto;\n      background: #f8fbff;\n      border: 1px solid rgba(37, 99, 235, 0.18);\n      border-radius: 14px;\n      padding: 10px 13px;\n      color: var(--navy);\n      font-weight: 700;\n      line-height: 1.7;\n      margin-top: 8px;\n      white-space: nowrap;\n    }\n\n    .ols-rate-strip {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 14px;\n      margin-top: 18px;\n    }\n\n    .ols-rate-pill {\n      border-radius: 18px;\n      padding: 16px;\n      border: 1px solid var(--border);\n      background: #ffffff;\n      box-shadow: var(--inner-shadow);\n    }\n\n    .ols-rate-pill small {\n      display: block;\n      color: var(--grey-text);\n      font-weight: 700;\n      margin-bottom: 6px;\n    }\n\n    .ols-rate-pill strong {\n      display: block;\n      font-size: 22px;\n      color: var(--navy);\n    }\n\n    .ols-rate-pill span {\n      display: block;\n      margin-top: 6px;\n      color: var(--body-text);\n      font-size: 14px;\n      line-height: 1.45;\n    }\n\n    .ols-interactive-card {\n      background: radial-gradient(circle at top right, rgba(37, 99, 235, 0.14), transparent 32%), linear-gradient(135deg, #ffffff 0%, #f7f0ff 100%);\n      border: 1px solid var(--border);\n      border-radius: 30px;\n      box-shadow: var(--shadow);\n      padding: 34px;\n      margin: 0 0 24px;\n      overflow: hidden;\n    }\n\n    .ols-interactive-head {\n      display: flex;\n      align-items: flex-start;\n      justify-content: space-between;\n      gap: 18px;\n      margin-bottom: 22px;\n    }\n\n    .ols-interactive-head h2 {\n      margin: 0 0 10px;\n      font-size: clamp(28px, 3.4vw, 42px);\n      line-height: 1.12;\n      letter-spacing: -0.03em;\n      color: #111827;\n    }\n\n    .ols-interactive-head p {\n      margin: 0;\n      font-size: 16px;\n      line-height: 1.65;\n      color: var(--body-text);\n      font-weight: 300;\n    }\n\n    .ols-reset-btn,\n    .ols-action-btn {\n      appearance: none;\n      border: none;\n      border-radius: 999px;\n      padding: 12px 16px;\n      font-family: Poppins, Arial, sans-serif;\n      font-size: 14px;\n      font-weight: 750;\n      cursor: pointer;\n      transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;\n    }\n\n    .ols-reset-btn {\n      background: #ffffff;\n      color: var(--navy);\n      border: 1px solid var(--border);\n      flex-shrink: 0;\n    }\n\n    .ols-reset-btn:hover,\n    .ols-action-btn:hover { transform: translateY(-2px); }\n\n    .ols-interactive-grid {\n      display: grid;\n      grid-template-columns: minmax(0, 1.15fr) minmax(280px, 0.85fr);\n      gap: 18px;\n      align-items: start;\n    }\n\n    .ols-interactive-panel {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 22px;\n      padding: 20px;\n      box-shadow: var(--inner-shadow);\n    }\n\n    .ols-interactive-panel h3 {\n      margin: 0 0 12px;\n      font-size: 22px;\n      color: var(--navy);\n    }\n\n    .ols-action-stack {\n      display: grid;\n      gap: 10px;\n    }\n\n    .ols-action-btn {\n      width: 100%;\n      text-align: left;\n      background: #ffffff;\n      color: var(--navy);\n      border: 1px solid rgba(37, 99, 235, 0.22);\n      box-shadow: 0 8px 16px rgba(28, 36, 75, 0.06);\n    }\n\n    .ols-action-btn.is-active {\n      background: var(--navy);\n      color: #ffffff;\n      border-color: var(--navy);\n    }\n\n    .ols-action-btn.is-pulse { animation: olsCp4Pulse 1.7s infinite; }\n\n    @keyframes olsCp4Pulse {\n      0% { box-shadow: 0 8px 16px rgba(28, 36, 75, 0.06), 0 0 0 0 rgba(37, 99, 235, 0.30); }\n      70% { box-shadow: 0 8px 16px rgba(28, 36, 75, 0.06), 0 0 0 10px rgba(37, 99, 235, 0.00); }\n      100% { box-shadow: 0 8px 16px rgba(28, 36, 75, 0.06), 0 0 0 0 rgba(37, 99, 235, 0.00); }\n    }\n\n    .ols-mini-results {\n      width: 100%;\n      border-collapse: collapse;\n      margin-top: 10px;\n      font-size: 14px;\n    }\n\n    .ols-mini-results th,\n    .ols-mini-results td {\n      border-bottom: 1px solid var(--border);\n      padding: 9px 7px;\n      text-align: left;\n      color: var(--body-text);\n      vertical-align: top;\n    }\n\n    .ols-mini-results th {\n      color: var(--navy);\n      font-weight: 800;\n    }\n\n    .ols-hidden-value { color: #98a2b3; font-weight: 500; }\n    .ols-visible-value { color: var(--navy); font-weight: 800; }\n    .ols-row-fast td { background: var(--soft-green); color: var(--navy); font-weight: 700; }\n    .ols-row-slow td { background: var(--soft-red); color: var(--navy); font-weight: 700; }\n\n    .ols-working-box {\n      background: #f8fbff;\n      border: 1px solid rgba(37, 99, 235, 0.18);\n      border-radius: 18px;\n      padding: 16px;\n      min-height: 210px;\n    }\n\n    .ols-working-box h4 {\n      margin: 0 0 10px;\n      font-size: 19px;\n      color: var(--navy);\n    }\n\n    .ols-working-box p {\n      margin: 0 0 10px;\n      font-size: 15px;\n      line-height: 1.65;\n      color: var(--body-text);\n    }\n\n    .ols-answer-pill {\n      display: inline-flex;\n      align-items: center;\n      gap: 8px;\n      padding: 10px 13px;\n      border-radius: 999px;\n      background: var(--soft-green);\n      color: var(--navy);\n      font-weight: 800;\n      border: 1px solid rgba(63, 143, 70, 0.25);\n      margin-top: 6px;\n    }\n\n    .ols-related-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 16px;\n      margin-top: 18px;\n    }\n\n    .ols-related-item {\n      border: 1px solid var(--border);\n      border-radius: 18px;\n      padding: 18px;\n      background: #ffffff;\n      color: var(--navy);\n      text-decoration: none;\n      font-weight: 700;\n      line-height: 1.45;\n      transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;\n    }\n\n    .ols-related-item:hover {\n      transform: translateY(-2px);\n      box-shadow: 0 10px 22px rgba(28, 36, 75, 0.08);\n      background: var(--soft-blue);\n    }\n\n    .ols-faq-list {\n      display: grid;\n      gap: 14px;\n      margin-top: 18px;\n    }\n\n    .ols-faq-item {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 18px;\n      padding: 18px;\n    }\n\n    .ols-faq-item h3 {\n      margin: 0 0 8px;\n      font-size: 19px;\n      color: var(--navy);\n    }\n\n    .ols-faq-item p { margin: 0; }\n\n    @media (max-width: 1050px) {\n      .ols-process-grid,\n      .ols-related-grid,\n      .ols-rate-strip {\n        grid-template-columns: repeat(2, minmax(0, 1fr));\n      }\n\n      .ols-interactive-grid { grid-template-columns: 1fr; }\n    }\n\n    @media (max-width: 760px) {\n      .ols-cp-shell { padding: 14px 12px 44px; }\n\n      .ols-title-card,\n      .ols-note-card,\n      .ols-related-card,\n      .ols-faq-card,\n      .ols-interactive-card {\n        padding: 24px 18px;\n        border-radius: 22px;\n      }\n\n      .ols-note-title,\n      .ols-interactive-head { align-items: flex-start; }\n      .ols-interactive-head { flex-direction: column; }\n      .ols-reset-btn { width: 100%; text-align: center; }\n\n      .ols-process-grid,\n      .ols-apparatus-grid,\n      .ols-error-grid,\n      .ols-qa-grid,\n      .ols-related-grid,\n      .ols-rate-strip {\n        grid-template-columns: 1fr;\n      }\n\n      .ols-figure-image { min-height: 200px; }\n      .ols-figure-image.contain { padding: 10px; }\n\n      .ols-figure-image.structure-classification-small img {\n        max-width: 100%;\n        max-height: none;\n      }\n      .ols-table { min-width: 620px; }\n\n      .ols-figure-card { border-radius: 22px; }\n      .ols-figure-image {\n        min-height: 240px;\n        padding: 14px;\n        border-radius: 22px 22px 0 0;\n      }\n      .ols-figure-caption { padding: 18px; }\n      .ols-cp4-lightbox { padding: 12px; }\n      .ols-cp4-lightbox p { display: none; }\n\n      .ols-author {\n        align-items: flex-start;\n        padding: 22px 18px;\n        border-radius: 22px;\n      }\n\n      .ols-author-avatar-img {\n        width: 72px;\n        height: 72px;\n      }\n\n      .ols-author-title { font-size: 24px; }\n      .ols-author-description { font-size: 15px; }\n    }\n  <\/style>\n\n  <div class=\"ols-cp-sidebar-shortcode\"><aside class=\"ols-sidebar\">\r\n  <div class=\"ols-sidebar-header\">\r\n    <h3>Revision Notes<\/h3>\r\n    <p>Edexcel A Level Chemistry<\/p>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Core Practicals<\/h4>\r\n    <ul class=\"ols-topic-list\">\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-1-molar-volume-of-a-gas\/\">CP1: Molar Volume of a Gas<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-2-prepare-a-standard-solution\/\">CP2: Prepare a Standard Solution<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-3-concentration-of-hcl-by-titration\/\">CP3: Concentration of HCl by Titration<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-4-hydrolysis-of-halogenoalkanes\/\">CP4: Hydrolysis of Halogenoalkanes<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-5-oxidation-of-ethanol\/\">CP5: Oxidation of Ethanol<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-6-chlorination-of-2-methylpropan-2-ol\/\">CP6: Chlorination of 2-methylpropan-2-ol<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-7-analysis-of-inorganic-and-organic-unknowns\/\">CP7: Analysis of Inorganic and Organic Unknowns<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-8-enthalpy-change-via-hess-law\/\">CP8: Enthalpy Change via Hess\u2019s Law<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-9-electrochemical-cells\/\">CP9: Electrochemical Cells<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-10-titration-of-edta\/\">CP10: Titration of EDTA<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-11-rates-of-reaction-clock\/\">CP11: Rates of Reaction (Clock)<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-12-continuous-monitoring-rates\/\">CP12: Continuous Monitoring Rates<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-13-preparation-of-aspirin\/\">CP13: Preparation of Aspirin<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-14-thin-layer-chromatography\/\">CP14: Thin Layer Chromatography<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-15-preparing-organic-compound\/\">CP15: Preparing Organic Compound<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/cp-16-testing-organic-unknowns\/\">CP16: Testing Organic Unknowns<\/a><\/li>\r\n    <\/ul>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Useful Links<\/h4>\r\n    <ul class=\"ols-topic-list\">\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/\">Edexcel A Level Chemistry<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/\">Core Practicals<\/a><\/li>\r\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-5-formulae-equations-and-amounts-of-substance\/\">Formulae, Equations and Amounts of Substance<\/a><\/li>\r\n    <\/ul>\r\n  <\/div>\r\n<\/aside>\r\n\r\n<script>\r\n(function () {\r\n  var sidebar = document.querySelector('.ols-sidebar');\r\n  if (!sidebar) return;\r\n\r\n  var currentPath = window.location.pathname.replace(\/\\\/$\/, '');\r\n\r\n  sidebar.querySelectorAll('.ols-topic-list li').forEach(function (li) {\r\n    li.classList.remove('active');\r\n\r\n    var link = li.querySelector('a');\r\n    if (!link) return;\r\n\r\n    var linkPath = new URL(link.href).pathname.replace(\/\\\/$\/, '');\r\n\r\n    if (linkPath === currentPath) {\r\n      li.classList.add('active');\r\n    }\r\n  });\r\n})();\r\n<\/script><\/div>\n\n  <div class=\"ols-cp-shell\">\n    <main class=\"ols-cp-main\">\n      <nav class=\"ols-breadcrumbs\" aria-label=\"Breadcrumb\">\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\">Revision Notes<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\">A Level Chemistry<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/\">Edexcel<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/core-practicals\/\">Core Practicals<\/a> \/\n        <span>CP4: Hydrolysis of Halogenoalkanes<\/span>\n      <\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>CP4: Hydrolysis of Halogenoalkanes<\/h1>\n        <p class=\"ols-page-intro\">In this core practical, you compare how quickly different halogenoalkanes hydrolyse. The rate is measured by timing how long it takes for a silver halide precipitate to appear after aqueous silver nitrate is added.<\/p>\n        <div class=\"ols-badges\">\n          <div class=\"ols-badge\">Exam board: Edexcel<\/div>\n          <div class=\"ols-badge\">Paper 3: General and Practical Principles in Chemistry<\/div>\n        <\/div>\n        <div class=\"ols-author\">\n          <img decoding=\"async\" class=\"ols-author-avatar-img\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\" alt=\"Dr. Mohammed Al-Fatah\">\n\n          <div class=\"ols-author-content\">\n            <h2 class=\"ols-author-title\">Written by: Dr. Mohammed Al-Fatah<\/h2>\n            <p class=\"ols-author-description\">Chemistry specialist revision notes for A Level Chemistry.<\/p>\n\n            <a class=\"ols-linkedin-pill\" href=\"https:\/\/www.linkedin.com\/in\/doctormohammedfatah\/\" target=\"_blank\" rel=\"noopener noreferrer\">\n              <svg class=\"ols-linkedin-icon\" viewBox=\"0 0 24 24\" fill=\"currentColor\" aria-hidden=\"true\">\n                <path d=\"M4.98 3.5C4.98 4.88 3.86 6 2.48 6S0 4.88 0 3.5 1.12 1 2.48 1s2.5 1.12 2.5 2.5zM.5 8h4V24h-4V8zm7 0h3.8v2.2h.1c.5-.9 1.8-2.2 3.9-2.2 4.2 0 5 2.8 5 6.4V24h-4v-7.6c0-1.8 0-4.2-2.6-4.2s-3 2-3 4v7.8h-4V8z\"><\/path>\n              <\/svg>\n              View LinkedIn Profile\n            <\/a>\n          <\/div>\n        <\/div>\n      <\/header>\n\n      <article class=\"ols-note-card soft\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">1<\/div>\n          <h2>What This Practical Is Testing<\/h2>\n        <\/div>\n        <p>This practical compares the <strong>relative rates of hydrolysis<\/strong> of different halogenoalkanes. Hydrolysis is the reaction of a molecule with water. For halogenoalkanes, water acts as a nucleophile and the product is an alcohol plus a halide ion.<\/p>\n        <p>The experiment has two linked comparisons. In <strong>Part 1<\/strong>, you compare primary chloro-, bromo- and iodoalkanes. In <strong>Part 2<\/strong>, you compare primary, secondary and tertiary bromoalkanes.<\/p>\n\n        <div class=\"ols-process-grid\" aria-label=\"CP4 practical process map\">\n          <div class=\"ols-process-step\">\n            <span>1<\/span>\n            <h3>Hydrolyse<\/h3>\n            <p>Water reacts with the halogenoalkane and releases a halide ion, X<sup>&#8211;<\/sup>.<\/p>\n          <\/div>\n          <div class=\"ols-process-step\">\n            <span>2<\/span>\n            <h3>Detect<\/h3>\n            <p>Ag<sup>+<\/sup> ions from silver nitrate react with X<sup>&#8211;<\/sup> to form a silver halide precipitate.<\/p>\n          <\/div>\n          <div class=\"ols-process-step\">\n            <span>3<\/span>\n            <h3>Compare<\/h3>\n            <p>The shorter the time taken for cloudiness to appear, the faster the hydrolysis reaction.<\/p>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Key idea:<\/strong> Silver nitrate does not cause the hydrolysis. It provides Ag<sup>+<\/sup> ions so the halide ion formed by hydrolysis can be detected as a precipitate.<\/p>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">2<\/div>\n          <h2>Safety and Apparatus<\/h2>\n        <\/div>\n        <p>Wear eye protection and avoid skin contact with the reactants. Ethanol and halogenoalkanes are highly flammable, so there must be <strong>no naked flames<\/strong>. The laboratory should also be well ventilated because halogenoalkanes can produce fumes.<\/p>\n\n        <div class=\"ols-apparatus-grid\">\n          <div class=\"ols-apparatus-card\">\n            <h3>Solutions and chemicals<\/h3>\n            <p>1-chlorobutane, 1-bromobutane, 1-iodobutane, 2-bromobutane, 2-bromo-2-methylpropane, ethanol and 0.05 mol dm<sup>-3<\/sup> silver nitrate solution.<\/p>\n          <\/div>\n          <div class=\"ols-apparatus-card\">\n            <h3>Equipment<\/h3>\n            <p>250 cm<sup>3<\/sup> beaker, test tubes with bungs, dropping pipettes, measuring cylinders, labels, stop clock and a kettle for preparing the warm water bath.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card green\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">3<\/div>\n          <h2>The Five Halogenoalkanes Used<\/h2>\n        <\/div>\n        <p>Before interpreting the results, identify which halogenoalkanes are primary, secondary and tertiary. This matters because Part 2 compares how the structure of the halogenoalkane affects the rate of hydrolysis.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Halogenoalkane<\/th>\n                <th>Classification<\/th>\n                <th>Where it is used<\/th>\n                <th>Comparison being made<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td><strong>1-chlorobutane<\/strong><\/td>\n                <td>Primary<\/td>\n                <td>Part 1<\/td>\n                <td>Effect of different halogens<\/td>\n              <\/tr>\n              <tr>\n                <td><strong>1-bromobutane<\/strong><\/td>\n                <td>Primary<\/td>\n                <td>Part 1 and Part 2<\/td>\n                <td>Halogen comparison and structure comparison<\/td>\n              <\/tr>\n              <tr>\n                <td><strong>1-iodobutane<\/strong><\/td>\n                <td>Primary<\/td>\n                <td>Part 1<\/td>\n                <td>Effect of different halogens<\/td>\n              <\/tr>\n              <tr>\n                <td><strong>2-bromobutane<\/strong><\/td>\n                <td>Secondary<\/td>\n                <td>Part 2<\/td>\n                <td>Effect of primary, secondary and tertiary structure<\/td>\n              <\/tr>\n              <tr>\n                <td><strong>2-bromo-2-methylpropane<\/strong><\/td>\n                <td>Tertiary<\/td>\n                <td>Part 2<\/td>\n                <td>Effect of primary, secondary and tertiary structure<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-figure-card\">\n          <div class=\"ols-figure-image contain structure-classification-small\">\n            <img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/06\/Chemical-structure-classification-table.webp\" alt=\"Chemical structure classification table showing primary, secondary and tertiary halogenoalkanes used in CP4.\">\n          <\/div>\n          <div class=\"ols-figure-caption\">\n            <h3>Primary, secondary and tertiary halogenoalkanes<\/h3>\n            <p>Use the carbon bonded to the halogen to classify the halogenoalkane. Primary, secondary and tertiary structures are compared in Part 2 of the practical.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">4<\/div>\n          <h2>Method: How the Rate Is Measured<\/h2>\n        <\/div>\n        <p>The reaction is carried out in a warm water bath at about <strong>50 \u00b0C<\/strong>. This keeps the temperature controlled, because temperature affects the rate of reaction.<\/p>\n\n        <div class=\"ols-process-grid\" aria-label=\"CP4 method sequence\">\n          <div class=\"ols-process-step\">\n            <span>1<\/span>\n            <h3>Prepare water bath<\/h3>\n            <p>Fill a 250 cm<sup>3<\/sup> beaker about three-quarters full with water at around 50 \u00b0C.<\/p>\n          <\/div>\n          <div class=\"ols-process-step\">\n            <span>2<\/span>\n            <h3>Add ethanol<\/h3>\n            <p>Add 5 cm<sup>3<\/sup> ethanol to each labelled test tube.<\/p>\n          <\/div>\n          <div class=\"ols-process-step\">\n            <span>3<\/span>\n            <h3>Add halogenoalkane<\/h3>\n            <p>Add four drops of the relevant halogenoalkane to each ethanol tube.<\/p>\n          <\/div>\n          <div class=\"ols-process-step\">\n            <span>4<\/span>\n            <h3>Warm both solutions<\/h3>\n            <p>Warm the halogenoalkane mixtures and silver nitrate test tubes in the same water bath.<\/p>\n          <\/div>\n          <div class=\"ols-process-step\">\n            <span>5<\/span>\n            <h3>Mix and time<\/h3>\n            <p>Add silver nitrate to the halogenoalkane mixture and start the stop clock at the same time.<\/p>\n          <\/div>\n          <div class=\"ols-process-step\">\n            <span>6<\/span>\n            <h3>Stop when cloudy<\/h3>\n            <p>Stop timing as soon as the solution becomes cloudy due to a silver halide precipitate.<\/p>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Technique point:<\/strong> The test tubes containing the reacting mixture should stay in the water bath while timing. Otherwise, the temperature may fall and the rate comparison becomes less reliable.<\/p>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card purple\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">5<\/div>\n          <h2>What Happens During Hydrolysis?<\/h2>\n        <\/div>\n        <p>Hydrolysis of a halogenoalkane is a <strong>nucleophilic substitution reaction<\/strong>. Water acts as the nucleophile because the oxygen atom has lone pairs of electrons. It attacks the electron-deficient carbon atom attached to the halogen.<\/p>\n        <p>The C-X bond breaks and the halide ion leaves. The products are an alcohol, a hydrogen ion and a halide ion.<\/p>\n        <span class=\"ols-equation\">R-X + H<sub>2<\/sub>O \u2192 R-OH + H<sup>+<\/sup> + X<sup>&#8211;<\/sup><\/span>\n        <span class=\"ols-equation\">CH<sub>3<\/sub>CH<sub>2<\/sub>CH<sub>2<\/sub>CH<sub>2<\/sub>Br + H<sub>2<\/sub>O \u2192 CH<sub>3<\/sub>CH<sub>2<\/sub>CH<sub>2<\/sub>CH<sub>2<\/sub>OH + H<sup>+<\/sup> + Br<sup>&#8211;<\/sup><\/span>\n\n        <div class=\"ols-figure-card\">\n          <div class=\"ols-figure-image\">\n            <img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/06\/Mechanism-of-nucleophilic-attack-reaction.webp\" alt=\"Mechanism of nucleophilic attack reaction showing water attacking the carbon bonded to a halogen in a halogenoalkane.\">\n          <\/div>\n          <div class=\"ols-figure-caption\">\n            <h3>Nucleophilic substitution by water<\/h3>\n            <p>The lone pair on oxygen attacks the \u03b4+ carbon. The C-X bond breaks, forming an alcohol, H<sup>+<\/sup> and X<sup>&#8211;<\/sup>.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card gold\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">6<\/div>\n          <h2>Why Ethanol, Water and Silver Nitrate Are Used<\/h2>\n        <\/div>\n        <p>Each chemical has a specific role. This is a common exam area because students often mix up the solvent, nucleophile and test reagent.<\/p>\n\n        <div class=\"ols-apparatus-grid\">\n          <div class=\"ols-apparatus-card\">\n            <h3>Ethanol<\/h3>\n            <p>Halogenoalkanes are insoluble in water. Ethanol helps the halogenoalkane dissolve so it can react with water molecules.<\/p>\n          <\/div>\n          <div class=\"ols-apparatus-card\">\n            <h3>Water<\/h3>\n            <p>Water is the nucleophile in this practical. It reacts with the halogenoalkane during hydrolysis.<\/p>\n          <\/div>\n          <div class=\"ols-apparatus-card\">\n            <h3>Silver nitrate<\/h3>\n            <p>Ag<sup>+<\/sup> ions react with the halide ion released during hydrolysis, forming a silver halide precipitate.<\/p>\n          <\/div>\n          <div class=\"ols-apparatus-card\">\n            <h3>Why not hydroxide?<\/h3>\n            <p>If hydroxide ions are present when AgNO<sub>3<\/sub> is added, a precipitate of silver oxide or silver hydroxide can interfere with the test.<\/p>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Exam wording:<\/strong> Do not write \u201cethanol is the nucleophile\u201d. In this practical, ethanol is used to help dissolve the halogenoalkane. Water is the nucleophile.<\/p>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card cyan\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">7<\/div>\n          <h2>How the Silver Halide Precipitate Shows the Rate<\/h2>\n        <\/div>\n        <p>The precipitate only appears after hydrolysis has produced halide ions. Therefore, the time taken for cloudiness to appear tells you how quickly the halogenoalkane has hydrolysed.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Halide ion formed<\/th>\n                <th>Silver halide precipitate<\/th>\n                <th>Colour<\/th>\n                <th>What it shows<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr>\n                <td>Cl<sup>&#8211;<\/sup><\/td>\n                <td>AgCl<\/td>\n                <td>White<\/td>\n                <td>A chloroalkane has hydrolysed.<\/td>\n              <\/tr>\n              <tr>\n                <td>Br<sup>&#8211;<\/sup><\/td>\n                <td>AgBr<\/td>\n                <td>Cream<\/td>\n                <td>A bromoalkane has hydrolysed.<\/td>\n              <\/tr>\n              <tr>\n                <td>I<sup>&#8211;<\/sup><\/td>\n                <td>AgI<\/td>\n                <td>Yellow<\/td>\n                <td>An iodoalkane has hydrolysed.<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-figure-card\">\n          <div class=\"ols-figure-image\">\n            <img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/06\/Precipitate-colours-in-halogenoalkanes-test.webp\" alt=\"Precipitate colours in the hydrolysis of halogenoalkanes showing cream, white and yellow silver halide precipitates.\">\n          <\/div>\n          <div class=\"ols-figure-caption\">\n            <h3>Precipitate colours in the halogenoalkane test<\/h3>\n            <p>Silver chloride is white, silver bromide is cream and silver iodide is yellow. The colour identifies the halide ion released during hydrolysis.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">8<\/div>\n          <h2>Part 1: Comparing Chloro-, Bromo- and Iodoalkanes<\/h2>\n        <\/div>\n        <p>In Part 1, the halogenoalkanes are all primary. This means the main variable is the halogen: chlorine, bromine or iodine.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Halogenoalkane<\/th>\n                <th>C-X bond<\/th>\n                <th>Time for precipitate to form \/ s<\/th>\n                <th>Rate conclusion<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr class=\"ols-highlight-fast\">\n                <td>1-iodobutane<\/td>\n                <td>C-I<\/td>\n                <td>52<\/td>\n                <td>Fastest<\/td>\n              <\/tr>\n              <tr>\n                <td>1-bromobutane<\/td>\n                <td>C-Br<\/td>\n                <td>87<\/td>\n                <td>Intermediate<\/td>\n              <\/tr>\n              <tr class=\"ols-highlight-slow\">\n                <td>1-chlorobutane<\/td>\n                <td>C-Cl<\/td>\n                <td>606<\/td>\n                <td>Slowest<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-rate-strip\">\n          <div class=\"ols-rate-pill\">\n            <small>C-I bond<\/small>\n            <strong>218 kJ mol<sup>-1<\/sup><\/strong>\n            <span>Weakest bond, so it breaks most easily.<\/span>\n          <\/div>\n          <div class=\"ols-rate-pill\">\n            <small>C-Br bond<\/small>\n            <strong>284 kJ mol<sup>-1<\/sup><\/strong>\n            <span>Intermediate bond strength and intermediate rate.<\/span>\n          <\/div>\n          <div class=\"ols-rate-pill\">\n            <small>C-Cl bond<\/small>\n            <strong>339 kJ mol<sup>-1<\/sup><\/strong>\n            <span>Strongest bond, so it breaks most slowly.<\/span>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Conclusion:<\/strong> The rate order is iodoalkane &gt; bromoalkane &gt; chloroalkane because the C-I bond is weakest and the C-Cl bond is strongest.<\/p>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card green\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">9<\/div>\n          <h2>Part 2: Comparing Primary, Secondary and Tertiary Bromoalkanes<\/h2>\n        <\/div>\n        <p>In Part 2, the halogen is kept the same because all three compounds are bromoalkanes. This means the main variable is whether the halogenoalkane is primary, secondary or tertiary.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Halogenoalkane<\/th>\n                <th>Classification<\/th>\n                <th>Time for precipitate to form \/ s<\/th>\n                <th>Rate conclusion<\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr class=\"ols-highlight-fast\">\n                <td>2-bromo-2-methylpropane<\/td>\n                <td>Tertiary<\/td>\n                <td>3<\/td>\n                <td>Fastest<\/td>\n              <\/tr>\n              <tr>\n                <td>2-bromobutane<\/td>\n                <td>Secondary<\/td>\n                <td>34<\/td>\n                <td>Intermediate<\/td>\n              <\/tr>\n              <tr class=\"ols-highlight-slow\">\n                <td>1-bromobutane<\/td>\n                <td>Primary<\/td>\n                <td>59<\/td>\n                <td>Slowest<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Conclusion:<\/strong> For these bromoalkanes, the observed rate order is tertiary &gt; secondary &gt; primary. A shorter time means a faster hydrolysis reaction.<\/p>\n        <\/div>\n\n        <div class=\"ols-figure-card\">\n          <div class=\"ols-figure-image\">\n            <img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/06\/Comparing-halogenoalkane-hydrolysis-rates.webp\" alt=\"Infographic comparing the rates of hydrolysis of halogenoalkanes using silver nitrate precipitate formation.\">\n          <\/div>\n          <div class=\"ols-figure-caption\">\n            <h3>Comparing rates using precipitate formation<\/h3>\n            <p>The faster the precipitate forms, the faster the halogenoalkane has hydrolysed. The timing data are used to rank the relative rates.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n      <section class=\"ols-interactive-card\" aria-label=\"Interactive CP4 data walkthrough\">\n        <div class=\"ols-interactive-head\">\n          <div>\n            <h2>Interactive: From Cloudiness to Rate Order<\/h2>\n            <p>Reveal the data in stages. The aim is to connect the time taken for the precipitate to appear with the rate of hydrolysis and the chemistry behind the trend.<\/p>\n          <\/div>\n          <button type=\"button\" class=\"ols-reset-btn\" id=\"olsCp4Reset\">Reset<\/button>\n        <\/div>\n\n        <div class=\"ols-interactive-grid\">\n          <div class=\"ols-interactive-panel\">\n            <h3>Results board<\/h3>\n            <p><strong>Part 1:<\/strong> Comparing primary chloro-, bromo- and iodoalkanes.<\/p>\n            <table class=\"ols-mini-results\" aria-label=\"Interactive Part 1 halogenoalkane data\">\n              <thead>\n                <tr>\n                  <th>Halogenoalkane<\/th>\n                  <th>Bond<\/th>\n                  <th>Time \/ s<\/th>\n                  <th>Rate<\/th>\n                <\/tr>\n              <\/thead>\n              <tbody>\n                <tr id=\"olsCp4P1I\"><td>1-iodobutane<\/td><td>C-I<\/td><td><span class=\"ols-hidden-value\" data-value=\"52\">?<\/span><\/td><td><span class=\"ols-hidden-value\" data-value=\"Fastest\">?<\/span><\/td><\/tr>\n                <tr id=\"olsCp4P1Br\"><td>1-bromobutane<\/td><td>C-Br<\/td><td><span class=\"ols-hidden-value\" data-value=\"87\">?<\/span><\/td><td><span class=\"ols-hidden-value\" data-value=\"Intermediate\">?<\/span><\/td><\/tr>\n                <tr id=\"olsCp4P1Cl\"><td>1-chlorobutane<\/td><td>C-Cl<\/td><td><span class=\"ols-hidden-value\" data-value=\"606\">?<\/span><\/td><td><span class=\"ols-hidden-value\" data-value=\"Slowest\">?<\/span><\/td><\/tr>\n              <\/tbody>\n            <\/table>\n\n            <p style=\"margin-top:18px;\"><strong>Part 2:<\/strong> Comparing primary, secondary and tertiary bromoalkanes.<\/p>\n            <table class=\"ols-mini-results\" aria-label=\"Interactive Part 2 halogenoalkane data\">\n              <thead>\n                <tr>\n                  <th>Halogenoalkane<\/th>\n                  <th>Type<\/th>\n                  <th>Time \/ s<\/th>\n                  <th>Rate<\/th>\n                <\/tr>\n              <\/thead>\n              <tbody>\n                <tr id=\"olsCp4P2T\"><td>2-bromo-2-methylpropane<\/td><td>Tertiary<\/td><td><span class=\"ols-hidden-value\" data-value=\"3\">?<\/span><\/td><td><span class=\"ols-hidden-value\" data-value=\"Fastest\">?<\/span><\/td><\/tr>\n                <tr id=\"olsCp4P2S\"><td>2-bromobutane<\/td><td>Secondary<\/td><td><span class=\"ols-hidden-value\" data-value=\"34\">?<\/span><\/td><td><span class=\"ols-hidden-value\" data-value=\"Intermediate\">?<\/span><\/td><\/tr>\n                <tr id=\"olsCp4P2P\"><td>1-bromobutane<\/td><td>Primary<\/td><td><span class=\"ols-hidden-value\" data-value=\"59\">?<\/span><\/td><td><span class=\"ols-hidden-value\" data-value=\"Slowest\">?<\/span><\/td><\/tr>\n              <\/tbody>\n            <\/table>\n          <\/div>\n\n          <div class=\"ols-interactive-panel\">\n            <h3>Walkthrough controls<\/h3>\n            <div class=\"ols-action-stack\">\n              <button type=\"button\" class=\"ols-action-btn is-pulse\" data-step=\"1\">1. Reveal Part 1 times<\/button>\n              <button type=\"button\" class=\"ols-action-btn\" data-step=\"2\">2. Rank C-I, C-Br and C-Cl<\/button>\n              <button type=\"button\" class=\"ols-action-btn\" data-step=\"3\">3. Connect rate to bond strength<\/button>\n              <button type=\"button\" class=\"ols-action-btn\" data-step=\"4\">4. Reveal Part 2 times<\/button>\n              <button type=\"button\" class=\"ols-action-btn\" data-step=\"5\">5. Rank primary, secondary and tertiary<\/button>\n              <button type=\"button\" class=\"ols-action-btn\" data-step=\"6\">6. Build the exam conclusion<\/button>\n            <\/div>\n          <\/div>\n        <\/div>\n\n        <div class=\"ols-interactive-panel\" style=\"margin-top:18px;\">\n          <div class=\"ols-working-box\" id=\"olsCp4Working\">\n            <h4>Start here<\/h4>\n            <p>Click the first button to reveal the Part 1 timing data. Remember: the precipitate forms only after hydrolysis has released a halide ion.<\/p>\n            <p class=\"ols-equation\">shorter time = faster hydrolysis<\/p>\n          <\/div>\n        <\/div>\n\n        <script>\n          (function(){\n            var root = document.currentScript.closest('.ols-interactive-card');\n            if (!root) return;\n            var buttons = root.querySelectorAll('.ols-action-btn');\n            var reset = root.querySelector('#olsCp4Reset');\n            var working = root.querySelector('#olsCp4Working');\n            var rows = ['olsCp4P1I','olsCp4P1Br','olsCp4P1Cl','olsCp4P2T','olsCp4P2S','olsCp4P2P'];\n\n            function revealRows(ids){\n              ids.forEach(function(id){\n                var row = root.querySelector('#' + id);\n                if (!row) return;\n                row.querySelectorAll('.ols-hidden-value').forEach(function(el){\n                  el.textContent = el.getAttribute('data-value');\n                  el.classList.remove('ols-hidden-value');\n                  el.classList.add('ols-visible-value');\n                });\n              });\n            }\n\n            function clearHighlights(){\n              rows.forEach(function(id){\n                var row = root.querySelector('#' + id);\n                if (row) row.classList.remove('ols-row-fast','ols-row-slow');\n              });\n            }\n\n            function setActive(step){\n              buttons.forEach(function(btn){\n                btn.classList.toggle('is-active', btn.getAttribute('data-step') === String(step));\n                btn.classList.remove('is-pulse');\n              });\n              var next = root.querySelector('.ols-action-btn[data-step=\"' + (Number(step) + 1) + '\"]');\n              if (next) next.classList.add('is-pulse');\n            }\n\n            function resetAll(){\n              rows.forEach(function(id){\n                var row = root.querySelector('#' + id);\n                if (!row) return;\n                row.classList.remove('ols-row-fast','ols-row-slow');\n                row.querySelectorAll('.ols-visible-value').forEach(function(el){\n                  el.textContent = '?';\n                  el.classList.remove('ols-visible-value');\n                  el.classList.add('ols-hidden-value');\n                });\n              });\n              buttons.forEach(function(btn){ btn.classList.remove('is-active','is-pulse'); });\n              var first = root.querySelector('.ols-action-btn[data-step=\"1\"]');\n              if (first) first.classList.add('is-pulse');\n              working.innerHTML = '<h4>Start here<\/h4><p>Click the first button to reveal the Part 1 timing data. Remember: the precipitate forms only after hydrolysis has released a halide ion.<\/p><p class=\"ols-equation\">shorter time = faster hydrolysis<\/p>';\n            }\n\n            buttons.forEach(function(btn){\n              btn.addEventListener('click', function(){\n                var step = Number(btn.getAttribute('data-step'));\n                clearHighlights();\n                setActive(step);\n\n                if (step === 1) {\n                  revealRows(['olsCp4P1I','olsCp4P1Br','olsCp4P1Cl']);\n                  working.innerHTML = '<h4>Step 1: Part 1 times<\/h4><p>The primary halogenoalkanes give times of 52 s, 87 s and 606 s.<\/p><p>The precipitate appears first for 1-iodobutane and last for 1-chlorobutane.<\/p>';\n                }\n\n                if (step === 2) {\n                  revealRows(['olsCp4P1I','olsCp4P1Br','olsCp4P1Cl']);\n                  root.querySelector('#olsCp4P1I').classList.add('ols-row-fast');\n                  root.querySelector('#olsCp4P1Cl').classList.add('ols-row-slow');\n                  working.innerHTML = '<h4>Step 2: Rank the rates<\/h4><p>A shorter time means faster hydrolysis.<\/p><p class=\"ols-answer-pill\">Rate order: iodoalkane &gt; bromoalkane &gt; chloroalkane<\/p>';\n                }\n\n                if (step === 3) {\n                  revealRows(['olsCp4P1I','olsCp4P1Br','olsCp4P1Cl']);\n                  root.querySelector('#olsCp4P1I').classList.add('ols-row-fast');\n                  root.querySelector('#olsCp4P1Cl').classList.add('ols-row-slow');\n                  working.innerHTML = '<h4>Step 3: Connect to bond strength<\/h4><p>C-I = 218 kJ mol<sup>-1<\/sup>, C-Br = 284 kJ mol<sup>-1<\/sup>, C-Cl = 339 kJ mol<sup>-1<\/sup>.<\/p><p>The C-I bond is weakest, so it breaks most easily. The C-Cl bond is strongest, so it breaks most slowly.<\/p>';\n                }\n\n                if (step === 4) {\n                  revealRows(['olsCp4P2T','olsCp4P2S','olsCp4P2P']);\n                  working.innerHTML = '<h4>Step 4: Part 2 times<\/h4><p>The bromoalkanes give times of 3 s, 34 s and 59 s.<\/p><p>The tertiary bromoalkane gives a precipitate first.<\/p>';\n                }\n\n                if (step === 5) {\n                  revealRows(['olsCp4P2T','olsCp4P2S','olsCp4P2P']);\n                  root.querySelector('#olsCp4P2T').classList.add('ols-row-fast');\n                  root.querySelector('#olsCp4P2P').classList.add('ols-row-slow');\n                  working.innerHTML = '<h4>Step 5: Rank structure<\/h4><p>For these bromoalkanes, the observed rate order is:<\/p><p class=\"ols-answer-pill\">tertiary &gt; secondary &gt; primary<\/p>';\n                }\n\n                if (step === 6) {\n                  revealRows(['olsCp4P1I','olsCp4P1Br','olsCp4P1Cl','olsCp4P2T','olsCp4P2S','olsCp4P2P']);\n                  root.querySelector('#olsCp4P1I').classList.add('ols-row-fast');\n                  root.querySelector('#olsCp4P1Cl').classList.add('ols-row-slow');\n                  root.querySelector('#olsCp4P2T').classList.add('ols-row-fast');\n                  root.querySelector('#olsCp4P2P').classList.add('ols-row-slow');\n                  working.innerHTML = '<h4>Step 6: Exam conclusion<\/h4><p>The rate is judged by the time taken for the precipitate to appear. A shorter time means faster hydrolysis.<\/p><p>In Part 1, iodoalkanes hydrolyse fastest because the C-I bond is weakest. In Part 2, the tertiary bromoalkane reacts fastest, followed by the secondary and then the primary bromoalkane.<\/p>';\n                }\n              });\n            });\n\n            if (reset) reset.addEventListener('click', resetAll);\n          })();\n        <\/script>\n      <\/section>\n\n      <article class=\"ols-note-card purple\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">10<\/div>\n          <h2>Exam-Style Data Interpretation<\/h2>\n        <\/div>\n        <p>A common exam version compares equal amounts of 2-chloropropane, 2-bromopropane and 2-iodopropane. The same logic applies: shorter time means faster hydrolysis.<\/p>\n\n        <div class=\"ols-table-wrap\">\n          <table class=\"ols-table\">\n            <thead>\n              <tr>\n                <th>Halogenoalkane<\/th>\n                <th>Time for precipitate to form \/ s<\/th>\n                <th>Halogen electronegativity<\/th>\n                <th>Mean C-halogen bond strength \/ kJ mol<sup>-1<\/sup><\/th>\n              <\/tr>\n            <\/thead>\n            <tbody>\n              <tr class=\"ols-highlight-fast\">\n                <td>2-iodopropane<\/td>\n                <td>31<\/td>\n                <td>2.7<\/td>\n                <td>218<\/td>\n              <\/tr>\n              <tr>\n                <td>2-bromopropane<\/td>\n                <td>74<\/td>\n                <td>3.0<\/td>\n                <td>284<\/td>\n              <\/tr>\n              <tr class=\"ols-highlight-slow\">\n                <td>2-chloropropane<\/td>\n                <td>241<\/td>\n                <td>3.2<\/td>\n                <td>339<\/td>\n              <\/tr>\n            <\/tbody>\n          <\/table>\n        <\/div>\n\n        <div class=\"ols-qa-grid\">\n          <div class=\"ols-qa-card\">\n            <h3>Why use equal moles?<\/h3>\n            <p>Equal moles means the concentration of halogenoalkane is equal in each experiment, so concentration does not affect the relative rates.<\/p>\n          <\/div>\n          <div class=\"ols-qa-card\">\n            <h3>Why is electronegativity not the controlling factor?<\/h3>\n            <p>Chlorine is most electronegative, so it would make the carbon most \u03b4+. If electronegativity controlled the rate, chloroalkanes would react fastest. The data show the opposite.<\/p>\n          <\/div>\n          <div class=\"ols-qa-card\">\n            <h3>Why does bond strength explain the trend?<\/h3>\n            <p>The carbon-halogen bond breaks during the reaction. A stronger bond is harder to break and gives a higher activation energy, so the reaction is slower.<\/p>\n          <\/div>\n          <div class=\"ols-qa-card\">\n            <h3>Final exam conclusion<\/h3>\n            <p>The C-I bond is weakest, so iodoalkanes hydrolyse fastest. The C-Cl bond is strongest, so chloroalkanes hydrolyse slowest.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">11<\/div>\n          <h2>Core Practical Questions and Answers<\/h2>\n        <\/div>\n        <p>Use these as compact revision checks. They cover the main questions students are expected to answer from the practical.<\/p>\n\n        <div class=\"ols-qa-grid\">\n          <div class=\"ols-qa-card\">\n            <h3>Write the equation for 1-bromobutane with water.<\/h3>\n            <p>CH<sub>3<\/sub>CH<sub>2<\/sub>CH<sub>2<\/sub>CH<sub>2<\/sub>Br + H<sub>2<\/sub>O \u2192 CH<sub>3<\/sub>CH<sub>2<\/sub>CH<sub>2<\/sub>CH<sub>2<\/sub>OH + H<sup>+<\/sup> + Br<sup>&#8211;<\/sup><\/p>\n          <\/div>\n          <div class=\"ols-qa-card\">\n            <h3>What precipitate forms from 1-iodobutane?<\/h3>\n            <p>Silver iodide, AgI. It is a yellow precipitate.<\/p>\n          <\/div>\n          <div class=\"ols-qa-card\">\n            <h3>Why is ethanol used?<\/h3>\n            <p>Halogenoalkanes are insoluble in water. Ethanol helps them dissolve so they can react with water molecules.<\/p>\n          <\/div>\n          <div class=\"ols-qa-card\">\n            <h3>Why can water act as a nucleophile?<\/h3>\n            <p>The oxygen atom in water has lone pairs of electrons that can attack the electron-deficient carbon atom.<\/p>\n          <\/div>\n          <div class=\"ols-qa-card\">\n            <h3>Why is water used rather than hydroxide ions?<\/h3>\n            <p>Hydroxide ions would form a precipitate with silver ions immediately, interfering with the silver nitrate test.<\/p>\n          <\/div>\n          <div class=\"ols-qa-card\">\n            <h3>Classify the five halogenoalkanes used.<\/h3>\n            <p>1-chlorobutane, 1-bromobutane and 1-iodobutane are primary. 2-bromobutane is secondary. 2-bromo-2-methylpropane is tertiary.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n\n      <article class=\"ols-note-card gold\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">12<\/div>\n          <h2>Common Mistakes<\/h2>\n        <\/div>\n\n        <div class=\"ols-error-grid\">\n          <div class=\"ols-error-card\">\n            <h3>Mistake: \u201cSilver nitrate causes hydrolysis.\u201d<\/h3>\n            <p><strong>Fix:<\/strong> Water hydrolyses the halogenoalkane. Silver nitrate detects the halide ion produced.<\/p>\n          <\/div>\n          <div class=\"ols-error-card\">\n            <h3>Mistake: \u201cYellow precipitate means iodine was present.\u201d<\/h3>\n            <p><strong>Fix:<\/strong> Yellow AgI means iodide ions formed after hydrolysis, so the original compound was an iodoalkane.<\/p>\n          <\/div>\n          <div class=\"ols-error-card\">\n            <h3>Mistake: \u201cElectronegativity controls the rate.\u201d<\/h3>\n            <p><strong>Fix:<\/strong> The data show bond strength is the better explanation here. C-I is weakest and reacts fastest.<\/p>\n          <\/div>\n          <div class=\"ols-error-card\">\n            <h3>Mistake: Forgetting ethanol\u2019s role.<\/h3>\n            <p><strong>Fix:<\/strong> Ethanol helps dissolve the halogenoalkane. It is not the nucleophile in the hydrolysis explanation.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n      <section class=\"ols-faq-card\">\n        <h2>CP4 FAQs<\/h2>\n        <div class=\"ols-faq-list\">\n          <div class=\"ols-faq-item\">\n            <h3>How is the rate measured in CP4?<\/h3>\n            <p>The rate is compared by measuring the time taken for a silver halide precipitate to appear. A shorter time means faster hydrolysis.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>Why does 1-iodobutane react faster than 1-chlorobutane?<\/h3>\n            <p>The C-I bond is weaker than the C-Cl bond, so it breaks more easily. This makes iodoalkanes hydrolyse faster than chloroalkanes.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>Why is ethanol used in the practical?<\/h3>\n            <p>Halogenoalkanes do not dissolve well in water. Ethanol helps dissolve the halogenoalkane so it can react with water.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>Why must there be no naked flames?<\/h3>\n            <p>Ethanol and halogenoalkanes are highly flammable, so naked flames would create a fire risk.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>What is the role of silver nitrate?<\/h3>\n            <p>Silver nitrate provides Ag<sup>+<\/sup> ions. These react with released halide ions to form silver halide precipitates.<\/p>\n          <\/div>\n        <\/div>\n      <\/section>\n    <\/main>\n  <\/div>\n\n  <div class=\"ols-cp4-lightbox\" id=\"olsCp4Lightbox\" aria-hidden=\"true\">\n    <button type=\"button\" aria-label=\"Close image\">&times;<\/button>\n    <img decoding=\"async\" src=\"\" alt=\"\">\n    <p><\/p>\n  <\/div>\n\n  <script>\n    (function(){\n      function initCp4Lightbox(){\n        var page = document.getElementById('ols-cp4-page');\n        if (!page) { return; }\n\n        var lb = page.querySelector('#olsCp4Lightbox');\n        if (!lb || lb.dataset.olsReady === '1') { return; }\n        lb.dataset.olsReady = '1';\n\n        var lbImg = lb.querySelector('img');\n        var lbText = lb.querySelector('p');\n        var closeBtn = lb.querySelector('button');\n\n        function openLightbox(img){\n          if (!img) { return; }\n          lbImg.src = img.currentSrc || img.src;\n          lbImg.alt = img.alt || '';\n          lbText.textContent = img.alt || 'Image preview';\n          lb.classList.add('is-open');\n          lb.setAttribute('aria-hidden', 'false');\n          document.documentElement.style.overflow = 'hidden';\n        }\n\n        function closeLightbox(){\n          lb.classList.remove('is-open');\n          lb.setAttribute('aria-hidden', 'true');\n          lbImg.src = '';\n          lbImg.alt = '';\n          lbText.textContent = '';\n          document.documentElement.style.overflow = '';\n        }\n\n        page.addEventListener('click', function(e){\n          var frame = e.target.closest('.ols-figure-image');\n          if (!frame || !page.contains(frame)) { return; }\n          var img = frame.querySelector('img');\n          openLightbox(img);\n        });\n\n        if (closeBtn) { closeBtn.addEventListener('click', closeLightbox); }\n        lb.addEventListener('click', function(e){\n          if (e.target === lb) { closeLightbox(); }\n        });\n        document.addEventListener('keydown', function(e){\n          if (e.key === 'Escape' && lb.classList.contains('is-open')) { closeLightbox(); }\n        });\n      }\n\n      if (document.readyState === 'loading') {\n        document.addEventListener('DOMContentLoaded', initCp4Lightbox);\n      } else {\n        initCp4Lightbox();\n      }\n    })();\n  <\/script>\n\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Revision Notes \/ A Level Chemistry \/ Edexcel \/ Core Practicals \/ CP4: Hydrolysis of Halogenoalkanes CP4: Hydrolysis of Halogenoalkanes In this core practical, you compare how quickly different halogenoalkanes hydrolyse. The rate is measured by timing how long it takes for a silver halide precipitate to appear after aqueous silver nitrate is added. Exam [&hellip;]<\/p>\n","protected":false},"author":12,"featured_media":0,"parent":4999,"menu_order":3,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-4507","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4507","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/users\/12"}],"replies":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/comments?post=4507"}],"version-history":[{"count":0,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4507\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4999"}],"wp:attachment":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/media?parent=4507"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}