{"id":10470,"date":"2026-09-26T11:30:17","date_gmt":"2026-09-26T10:30:17","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/"},"modified":"2026-10-04T23:02:28","modified_gmt":"2026-10-04T22:02:28","slug":"8a-redox-chemistry","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/","title":{"rendered":"Topic 8A Redox Chemistry"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-topic-8a-landing-page\">\n  <style>\n    .ols-revision-page {\n      --navy: #1C244B;\n      --blue: #2563eb;\n      --soft-blue: #eef4ff;\n      --soft-red: #fff7f7;\n      --soft-purple: #f7f0ff;\n      --soft-green: #f0f7f1;\n      --soft-orange: #fff7ed;\n      --gold: #c9973a;\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-revision-page * { box-sizing: border-box; }\n\n    .ols-revision-layout {\n      display: block;\n      max-width: 1450px;\n      margin: 0 auto;\n      padding: 24px 20px 60px;\n    }\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-attribution-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: hidden;\n    }\n\n    .ols-title-card {\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n    }\n\n    .ols-title-card h1 {\n      margin: 0 0 18px;\n      font-size: clamp(36px, 5vw, 58px);\n      line-height: 1.08;\n      font-weight: 800;\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: 600;\n      color: var(--navy);\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: 0 14px 32px rgba(28,36,75,0.18), 0 0 0 1px rgba(28,36,75,0.10);\n      transition: transform 0.25s ease, box-shadow 0.25s ease;\n    }\n\n    .ols-author:hover .ols-author-avatar-img {\n      transform: scale(1.04);\n      box-shadow: 0 20px 42px rgba(28,36,75,0.22), 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: transform 0.22s ease, 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(120deg, rgba(255,255,255,0) 0%, rgba(255,255,255,0.28) 50%, rgba(255,255,255,0) 100%);\n      transition: left 0.7s ease;\n    }\n\n    .ols-linkedin-pill:hover {\n      transform: translateY(-3px) scale(1.03);\n      box-shadow: 0 16px 34px rgba(10,102,194,0.34), 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    .ols-note-card.soft { background: linear-gradient(135deg, #ffffff 0%, var(--soft-red) 100%); }\n    .ols-note-card.purple { background: linear-gradient(135deg, #ffffff 0%, var(--soft-purple) 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      margin: 0;\n      font-size: clamp(28px, 3.5vw, 42px);\n      line-height: 1.15;\n      font-weight: 800;\n      color: #111827;\n      letter-spacing: -0.03em;\n    }\n\n    .ols-related-card h2 { margin-bottom: 14px; }\n\n    .ols-note-card p,\n    .ols-note-card li,\n    .ols-related-card p,\n    .ols-attribution-card p {\n      font-size: clamp(15px, 1.3vw, 18px);\n      line-height: 1.65;\n      font-weight: 300;\n      color: var(--body-text);\n    }\n\n    .ols-note-card strong,\n    .ols-related-card strong,\n    .ols-attribution-card strong {\n      font-weight: 700;\n      color: var(--navy);\n    }\n\n    .ols-key-box {\n      margin-top: 20px;\n      background: var(--soft-green);\n      border: 1px solid rgba(63, 143, 70, 0.25);\n      border-radius: 20px;\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-ert-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 18px;\n      margin-top: 26px;\n    }\n\n    .ols-ert-card {\n      position: relative;\n      display: grid;\n      grid-template-rows: auto 1fr auto;\n      min-height: 285px;\n      padding: 24px;\n      border-radius: 24px;\n      border: 1px solid rgba(28, 36, 75, 0.13);\n      background:\n        radial-gradient(circle at top right, rgba(37, 99, 235, 0.13), transparent 34%),\n        linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n      color: var(--navy);\n      text-decoration: none;\n      overflow: hidden;\n      box-shadow: var(--inner-shadow);\n      transition: transform 0.24s ease, box-shadow 0.24s ease, border-color 0.24s ease, background 0.24s ease;\n    }\n\n    .ols-ert-card:hover {\n      transform: translateY(-6px);\n      border-color: rgba(37, 99, 235, 0.28);\n      box-shadow: 0 24px 52px rgba(28, 36, 75, 0.15);\n      color: var(--navy);\n    }\n\n    .ols-ert-card::before {\n      content: \"\";\n      position: absolute;\n      top: -60px;\n      right: -60px;\n      width: 145px;\n      height: 145px;\n      border-radius: 50%;\n      background: rgba(37, 99, 235, 0.08);\n      transition: transform 0.28s ease, background 0.28s ease;\n    }\n\n    .ols-ert-card:hover::before {\n      transform: scale(1.22);\n      background: rgba(37, 99, 235, 0.13);\n    }\n\n    .ols-ert-visual {\n      position: relative;\n      z-index: 1;\n      min-height: 94px;\n      display: flex;\n      align-items: center;\n      justify-content: center;\n      margin-bottom: 18px;\n    }\n\n    .ols-ert-icon {\n      position: relative;\n      width: 150px;\n      height: 94px;\n    }\n\n    .ols-ert-line,\n    .ols-ert-arrow,\n    .ols-ert-label-mini,\n    .ols-ert-ion,\n    .ols-ert-pull,\n    .ols-ert-lattice {\n      position: absolute;\n      display: block;\n    }\n\n    .ols-ert-ionic .ols-ert-ion {\n      width: 40px;\n      height: 40px;\n      border-radius: 50%;\n      display: grid;\n      place-items: center;\n      font-size: 15px;\n      font-weight: 800;\n      color: #ffffff;\n      box-shadow: 0 12px 24px rgba(28,36,75,0.14);\n    }\n\n    .ols-ert-ionic .ols-ert-ion.left {\n      left: 24px;\n      top: 24px;\n      background: var(--blue);\n    }\n\n    .ols-ert-ionic .ols-ert-ion.right {\n      right: 24px;\n      top: 24px;\n      background: var(--gold);\n    }\n\n    .ols-ert-ionic .ols-ert-arrow {\n      left: 68px;\n      top: 43px;\n      width: 36px;\n      height: 3px;\n      border-radius: 999px;\n      background: rgba(28, 36, 75, 0.65);\n    }\n\n    .ols-ert-ionic .ols-ert-arrow::after {\n      content: \"\";\n      position: absolute;\n      right: -1px;\n      top: 50%;\n      transform: translateY(-50%);\n      border-left: 10px solid rgba(28,36,75,0.65);\n      border-top: 6px solid transparent;\n      border-bottom: 6px solid transparent;\n    }\n\n    .ols-ert-ionic .ols-ert-label-mini {\n      left: 39px;\n      bottom: 8px;\n      color: var(--blue);\n      font-size: 13px;\n      font-weight: 800;\n    }\n\n    .ols-ert-polarisation .ols-ert-ion.large {\n      left: 21px;\n      top: 18px;\n      width: 58px;\n      height: 58px;\n      border-radius: 50%;\n      border: 3px solid rgba(37, 99, 235, 0.34);\n      background: rgba(238, 244, 255, 0.96);\n      box-shadow: inset -10px 0 0 rgba(37,99,235,0.10), 0 12px 24px rgba(28,36,75,0.10);\n    }\n\n    .ols-ert-polarisation .ols-ert-ion.small {\n      right: 33px;\n      top: 30px;\n      width: 34px;\n      height: 34px;\n      border-radius: 50%;\n      background: var(--gold);\n      box-shadow: 0 10px 22px rgba(201,151,58,0.20);\n    }\n\n    .ols-ert-polarisation .ols-ert-pull {\n      left: 82px;\n      top: 44px;\n      width: 34px;\n      height: 3px;\n      border-radius: 999px;\n      background: rgba(201,151,58,0.88);\n    }\n\n    .ols-ert-polarisation .ols-ert-pull::before,\n    .ols-ert-polarisation .ols-ert-pull::after {\n      content: \"\";\n      position: absolute;\n      top: 50%;\n      transform: translateY(-50%);\n      border-top: 6px solid transparent;\n      border-bottom: 6px solid transparent;\n    }\n\n    .ols-ert-polarisation .ols-ert-pull::before {\n      left: -1px;\n      border-right: 10px solid rgba(201,151,58,0.88);\n    }\n\n    .ols-ert-polarisation .ols-ert-pull::after {\n      right: -1px;\n      border-left: 10px solid rgba(201,151,58,0.88);\n    }\n\n    .ols-ert-polarisation .ols-ert-label-mini {\n      left: 34px;\n      bottom: 8px;\n      color: var(--gold);\n      font-size: 13px;\n      font-weight: 800;\n    }\n\n    .ols-ert-properties .ols-ert-lattice {\n      left: 31px;\n      top: 13px;\n      width: 88px;\n      height: 68px;\n      background:\n        radial-gradient(circle at 12px 12px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 44px 12px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 76px 12px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 12px 36px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 44px 36px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 76px 36px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 12px 60px, var(--blue) 0 7px, transparent 8px),\n        radial-gradient(circle at 44px 60px, var(--gold) 0 7px, transparent 8px),\n        radial-gradient(circle at 76px 60px, var(--blue) 0 7px, transparent 8px);\n      border-radius: 18px;\n      box-shadow: 0 12px 26px rgba(28,36,75,0.10);\n    }\n\n    .ols-ert-properties .ols-ert-lattice::before {\n      content: \"\";\n      position: absolute;\n      inset: 8px 6px;\n      background:\n        linear-gradient(90deg, rgba(28,36,75,0.16) 1px, transparent 1px) 0 0 \/ 32px 24px,\n        linear-gradient(0deg, rgba(28,36,75,0.16) 1px, transparent 1px) 0 0 \/ 32px 24px;\n      border-radius: 14px;\n      pointer-events: none;\n    }\n\n    .ols-ert-properties .ols-ert-label-mini {\n      left: 43px;\n      bottom: 7px;\n      color: var(--blue);\n      font-size: 13px;\n      font-weight: 800;\n    }\n\n    .ols-ert-card h3 {\n      position: relative;\n      z-index: 1;\n      margin: 0 0 10px;\n      font-size: 23px;\n      line-height: 1.2;\n      font-weight: 800;\n      letter-spacing: -0.02em;\n      color: #111827;\n    }\n\n    .ols-ert-card p {\n      position: relative;\n      z-index: 1;\n      margin: 0;\n      font-size: 15px;\n      line-height: 1.6;\n      font-weight: 300;\n      color: var(--body-text);\n    }\n\n    .ols-ert-card,\n    .ols-ert-card *,\n    .ols-ert-card:hover,\n    .ols-ert-card:hover *,\n    .ols-related-item,\n    .ols-related-item *,\n    .ols-related-item:hover,\n    .ols-related-item:hover * {\n      text-decoration: none !important;\n    }\n\n    .ols-ert-meta {\n      position: relative;\n      z-index: 1;\n      display: inline-flex;\n      align-items: center;\n      justify-content: center;\n      margin-top: 20px;\n      padding: 10px 14px;\n      border-radius: 999px;\n      background: var(--navy);\n      color: #ffffff;\n      font-size: 13px;\n      font-weight: 700;\n      width: fit-content;\n      transition: background 0.22s ease, transform 0.22s ease;\n    }\n\n    .ols-ert-card:hover .ols-ert-meta {\n      background: var(--blue);\n      transform: translateX(4px);\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: 600;\n      line-height: 1.5;\n      transition: transform 0.2s ease, box-shadow 0.2s ease, color 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      color: var(--blue);\n    }\n\n    .ols-attribution-card {\n      background: linear-gradient(135deg, #ffffff 0%, #f8fbff 100%);\n    }\n\n    .ols-attribution-card p {\n      margin: 0;\n      font-size: 14px;\n      color: var(--grey-text);\n    }\n\n    @media (max-width: 1050px) {\n      .ols-revision-layout { grid-template-columns: 1fr; }\n      .ols-main { max-width: none; }\n      .ols-ert-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }\n      .ols-related-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }\n    }\n\n    @media (max-width: 760px) {\n      .ols-revision-layout { padding: 14px 12px 44px; }\n      .ols-title-card, .ols-note-card, .ols-related-card, .ols-attribution-card { padding: 24px 18px; border-radius: 22px; }\n      .ols-note-title { align-items: flex-start; }\n      .ols-author { align-items: flex-start; padding: 22px 18px; border-radius: 22px; }\n      .ols-author-avatar-img { width: 72px; height: 72px; }\n      .ols-author-title { font-size: 24px; }\n      .ols-author-description { font-size: 15px; }\n      .ols-ert-grid { grid-template-columns: 1fr; }\n      .ols-ert-card { min-height: 255px; }\n      .ols-related-grid { grid-template-columns: 1fr; }\n    }\n  :root { --ols-navy: #1C244B; --ols-blue: #467FF7; --ols-soft-blue: #EEF4FF; --ols-border: rgba(28, 36, 75, 0.12); --ols-shadow: 0 18px 45px rgba(28, 36, 75, 0.12); --ols-shadow-soft: 0 10px 28px rgba(28, 36, 75, 0.09); --ols-muted: #4b5575; }\n    .ols-sub-cards-grid { margin-top: 26px; }\n    .ols-sub-cards-grid {\n      display: grid;\n      grid-template-columns: repeat(3, minmax(0, 1fr));\n      gap: 20px;\n    }\n\n    .ols-sub-card {\n      display: flex;\n      flex-direction: column;\n      background: #ffffff;\n      border: 1px solid var(--ols-border);\n      border-radius: 22px;\n      overflow: hidden;\n      box-shadow: var(--ols-shadow-soft);\n      text-decoration: none;\n      color: var(--ols-navy);\n      transition:\n        transform 0.28s cubic-bezier(0.34, 1.56, 0.64, 1),\n        box-shadow 0.28s ease,\n        border-color 0.28s ease;\n      position: relative;\n    }\n\n    .ols-sub-card.ols-sub-card--available:hover {\n      transform: translateY(-10px) scale(1.02);\n      box-shadow: 0 28px 56px rgba(28, 36, 75, 0.16);\n      border-color: rgba(70, 127, 247, 0.35);\n    }\n\n    .ols-sub-card.ols-sub-card--available:hover .ols-sub-card-img-wrap::after {\n      opacity: 1;\n    }\n\n    .ols-sub-card-img-wrap {\n      position: relative;\n      width: 100%;\n      aspect-ratio: 4 \/ 3;\n      background: var(--ols-soft-blue);\n      overflow: hidden;\n    }\n\n    .ols-sub-card-img-wrap::after {\n      content: \"\";\n      position: absolute;\n      inset: 0;\n      background: linear-gradient(180deg, transparent 40%, rgba(28, 36, 75, 0.20) 100%);\n      opacity: 0;\n      transition: opacity 0.28s ease;\n      z-index: 1;\n    }\n\n    .ols-sub-card-num {\n      position: absolute;\n      top: 12px;\n      left: 12px;\n      width: 32px;\n      height: 32px;\n      border-radius: 50%;\n      background: var(--ols-navy);\n      color: #ffffff;\n      font-size: 13px;\n      font-weight: 800;\n      display: flex;\n      align-items: center;\n      justify-content: center;\n      z-index: 3;\n      box-shadow: 0 4px 12px rgba(28, 36, 75, 0.28);\n    }\n\n    .ols-sub-card-status {\n      position: absolute;\n      top: 12px;\n      right: 12px;\n      padding: 4px 10px;\n      border-radius: 999px;\n      font-size: 10px;\n      font-weight: 700;\n      z-index: 3;\n    }\n\n    .ols-sub-card-status--available {\n      background: #eaf3de;\n      color: #3B6D11;\n    }\n\n    .ols-sub-card-body {\n      padding: 18px 18px 22px;\n      flex: 1;\n      display: flex;\n      flex-direction: column;\n      gap: 6px;\n    }\n\n    .ols-sub-card-title {\n      font-size: 14px;\n      font-weight: 700;\n      color: var(--ols-navy);\n      line-height: 1.35;\n      margin: 0;\n    }\n\n    .ols-sub-card-desc {\n      font-size: 12px;\n      font-weight: 300;\n      color: var(--ols-muted);\n      line-height: 1.6;\n      margin: 0;\n    }\n\n    .ols-sub-card-cta {\n      display: inline-flex;\n      align-items: center;\n      gap: 5px;\n      margin-top: 10px;\n      font-size: 12px;\n      font-weight: 700;\n      color: var(--ols-blue);\n    }\n\n    .ols-sub-card-cta svg {\n      width: 14px;\n      height: 14px;\n      transition: transform 0.2s ease;\n    }\n\n    .ols-sub-card--available:hover .ols-sub-card-cta svg {\n      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var(--ols-navy);\n    }\n\n    \/* =========================================================\n       SPECIFICATION SECTION\n    ========================================================= *\/\n    @media (max-width: 1024px) { .ols-sub-cards-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } }\n    @media (max-width: 640px) { .ols-sub-cards-grid { grid-template-columns: 1fr; gap: 14px; } }\n    .ols-sub-card, .ols-sub-card *, .ols-sub-card:hover, .ols-sub-card:hover * { text-decoration: none !important; }\n    .ols-sub-card--soon { filter: grayscale(1); opacity: 0.62; cursor: not-allowed; }\n    .ols-sub-card-status--soon { background: #6b7280; color: #ffffff; }\n    .ols-sub-cards-grid .ols-sub-visual-main.ols-sub-visual-main { font-size: clamp(19px, 1.9vw, 26px) !important; line-height: 1.08; }\n    .ols-sub-cards-grid .ols-sub-visual-panel { width: min(86%, 270px); padding: 14px; }\n    .ols-sub-card .ols-sub-card-title.ols-sub-card-title { font-size: 14px; font-weight: 700; color: #1C244B; line-height: 1.35; margin: 0; }\n    .ols-sub-card .ols-sub-card-desc.ols-sub-card-desc { font-size: 12px; font-weight: 300; color: #4b5575; line-height: 1.6; margin: 0; }\n    .ols-sub-cards-grid .ols-sub-visual-main.ols-sub-visual-main--long { font-size: clamp(15px, 1.35vw, 19px) !important; line-height: 1.12; letter-spacing: -0.03em; }\n    .ols-sub-cards-grid .ols-sub-visual-main.ols-sub-visual-main--mid { font-size: clamp(17px, 1.6vw, 22px) !important; }\n    .ols-sub-cards-grid .ols-sub-visual-sub { font-size: 11px; line-height: 1.35; }\n<\/style>\n\n  <aside class=\"ols-sidebar\">\n  <div class=\"ols-sidebar-header\">\n    <h3>Revision Notes<\/h3>\n    <p>A Level Chemistry<\/p>\n  <\/div>\n\n  <div class=\"ols-topic-group\">\n    <h4>Topic 8 Redox &amp; Groups 1, 2 and 7<\/h4>\n\n    <ul class=\"ols-topic-list\">\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/\">Topic 8 Overview<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/\">Topic 8A Redox Chemistry<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/oxidation-numbers\/\">Oxidation Numbers<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/electron-transfer-and-half-equations\/\">Electron Transfer and Half-Equations<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/disproportionation\/\">Disproportionation<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/redox-classification\/\">Redox Classification<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/\">Topic 8B Groups 1 and 2<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/trends-down-groups-1-and-2\/\">Trends Down Groups 1 and 2<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/reactions-of-the-group-1-and-2-elements\/\">Reactions of the Group 1 and 2 Elements<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/oxides-hydroxides-and-carbonates\/\">Oxides, Hydroxides and Carbonates<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/solubility-trends-and-the-sulfate-test\/\">Solubility Trends and the Sulfate Test<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/thermal-stability-and-flame-colours\/\">Thermal Stability and Flame Colours<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/tests-for-ions\/\">Tests for Ions<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/titrations-and-measurement-uncertainty\/\">Titrations and Measurement Uncertainty<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-3-concentration-of-hcl-by-titration\/\">Core Practical 3<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-4-preparation-of-a-standard-solution\/\">Core Practical 4<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/\">Topic 8C Group 7<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/trends-in-the-halogens\/\">Trends in the Halogens<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/halogens-as-oxidising-agents\/\">Halogens as Oxidising Agents<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/disproportionation-reactions-of-chlorine\/\">Disproportionation Reactions of Chlorine<\/a>\n          <\/li>\n          <li>\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/halide-ions-reducing-agents-and-tests\/\">Halide Ions: Reducing Agents and Tests<\/a>\n          <\/li>\n        <\/ul>\n      <\/li>\n    <\/ul>\n  <\/div>\n\n  <div class=\"ols-topic-group\">\n    <h4>Other Topics<\/h4>\n\n    <ul class=\"ols-topic-list\">\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-6-energetics\/\">Topic 6 Energetics<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-7-intermolecular-forces\/\">Topic 7 Intermolecular Forces<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-2-atomic-structure-and-the-periodic-table\/\">Topic 2 Atomic Structure &amp; The Periodic Table<\/a>\n      <\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/\">Core Practicals<\/a>\n      <\/li>\n    <\/ul>\n  <\/div>\n<\/aside>\n\n<script>\r\n(function() {\r\n  function normalisePath(path) {\r\n    return String(path || '')\r\n      .split('?')[0]\r\n      .split('#')[0]\r\n      .replace(\/\\\/+$\/, '')\r\n      .toLowerCase();\r\n  }\r\n\r\n  function highlightActive() {\r\n    var sidebar = document.querySelector('.ols-sidebar');\r\n    if (!sidebar) return false;\r\n\r\n    var currentPath = normalisePath(window.location.pathname);\r\n    var links = sidebar.querySelectorAll('a[href]');\r\n    var matched = null;\r\n    var matchedLength = 0;\r\n\r\n    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'active-main');\r\n          matched.setAttribute('aria-current', 'page');\r\n          matched.setAttribute('tabindex', '-1');\r\n          matched.setAttribute('data-ols-disabled-parent', '1');\r\n        }\r\n      }\r\n    }\r\n\r\n    return true;\r\n  }\r\n\r\n  if (!highlightActive()) {\r\n    document.addEventListener('DOMContentLoaded', highlightActive);\r\n  }\r\n})();\r\n<\/script>\r\n\n\n  <main class=\"ols-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-international\/\">Edexcel International<\/a> \/\n      <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/\">Topic 8 Redox Chemistry and Groups 1, 2 and 7<\/a> \/\n      <span>Topic 8A Redox Chemistry<\/span>\n    <\/nav>\n\n    <header class=\"ols-title-card\">\n      <h1>Topic 8A Redox Chemistry<\/h1>\n      <p class=\"ols-page-intro\">Use this landing page to move between the four Redox Chemistry revision pages of Topic 8. Each card links to a focused page with inline checks, worked examples and exam-style FAQs.<\/p>\n\n      <div class=\"ols-badges\">\n        <div class=\"ols-badge\">Exam board: Edexcel International<\/div>\n        <div class=\"ols-badge\">Unit 2: WCH12\/01<\/div>\n        <div class=\"ols-badge\">Topic 8A Redox Chemistry<\/div>\n      <\/div>\n\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:<br><span>Dr. Mohammed Al-Fatah<\/span><\/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>Choose a Redox Chemistry Page<\/h2>\n      <\/div>\n\n      <p>Redox chemistry gives you a way of following electrons through a reaction. These pages build the oxidation number rules, then use them to define oxidation and reduction, to write and combine half-equations, to recognise disproportionation and to classify unfamiliar reactions.<\/p>\n\n      <div class=\"ols-key-box\">\n        <p><strong>Key idea:<\/strong> Every redox question comes back to the same two ideas: an increase in oxidation number is oxidation and a loss of electrons, a decrease is reduction and a gain of electrons.<\/p>\n      <\/div>\n\n      <div class=\"ols-sub-cards-grid\">\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/oxidation-numbers\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">Bookkeeping<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Oxidation Numbers<\/div>\n                <div class=\"ols-sub-visual-sub\">rules, ions, Roman numerals<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">1<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Oxidation Numbers<\/p>\n            <p class=\"ols-sub-card-desc\">Oxidation numbers: the rules, calculating them in compounds, ions, peroxides and metal hydrides, Roman numerals and writing formulae.<\/p>\n            <span class=\"ols-sub-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/electron-transfer-and-half-equations\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">OIL RIG<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Electron Transfer<\/div>\n                <div class=\"ols-sub-visual-sub\">half-equations and agents<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">2<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Electron Transfer and Half-Equations<\/p>\n            <p class=\"ols-sub-card-desc\">Redox as electron transfer: oxidising and reducing agents, oxidation number changes, writing ionic half-equations and combining them into full ionic equations.<\/p>\n            <span class=\"ols-sub-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/disproportionation\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">Both ways at once<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Dispropor- tionation<\/div>\n                <div class=\"ols-sub-visual-sub\">Cl\u2082, H\u2082O\u2082, Cu\u207a<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">3<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Disproportionation<\/p>\n            <p class=\"ols-sub-card-desc\">Disproportionation: recognising it with oxidation numbers, chlorine in water and alkali, hydrogen peroxide, copper(I) and which species cannot disproportionate.<\/p>\n            <span class=\"ols-sub-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n\n        <a class=\"ols-sub-card ols-sub-card--available\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/redox-classification\/\">\n          <div class=\"ols-sub-card-img-wrap\">\n            <div class=\"ols-sub-visual ols-sub-visual--particles\">\n              <div class=\"ols-sub-visual-panel\">\n                <div class=\"ols-sub-visual-kicker\">Redox or not?<\/div>\n                <div class=\"ols-sub-particle-diagram\" aria-hidden=\"true\"><span class=\"ols-sub-particle-dot d1\"><\/span><span class=\"ols-sub-particle-dot d2\"><\/span><span class=\"ols-sub-particle-dot d3\"><\/span><\/div>\n                <div class=\"ols-sub-visual-main ols-sub-visual-main--mid\">Redox Classification<\/div>\n                <div class=\"ols-sub-visual-sub\">metals, acids, unfamiliar equations<\/div>\n              <\/div>\n            <\/div>\n            <div class=\"ols-sub-card-num\">4<\/div>\n            <span class=\"ols-sub-card-status ols-sub-card-status--available\">Available<\/span>\n          <\/div>\n          <div class=\"ols-sub-card-body\">\n            <p class=\"ols-sub-card-title\">Redox Classification<\/p>\n            <p class=\"ols-sub-card-desc\">Classifying reactions with oxidation numbers: redox or not, s-block and p-block examples, metals with acids, and unfamiliar equations.<\/p>\n            <span class=\"ols-sub-card-cta\">\n              Start revising\n              <svg viewBox=\"0 0 16 16\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M3 8h10M9 4l4 4-4 4\"><\/path><\/svg>\n            <\/span>\n          <\/div>\n        <\/a>\n        <\/div>\n    <\/article>\n\n    <article class=\"ols-note-card purple\">\n      <div class=\"ols-note-title\">\n        <div class=\"ols-note-icon\">\u2713<\/div>\n        <h2>How to Use These Pages<\/h2>\n      <\/div>\n\n      <p>Start with the oxidation number rules until you can assign a value to any atom quickly. Then use electron transfer and half-equations to describe what the electrons do, disproportionation for the special case of one element going both ways, and redox classification to practise on equations you have not seen before.<\/p>\n\n      <div class=\"ols-key-box\">\n        <p><strong>Exam focus:<\/strong> In a redox explanation always quote the element, its two oxidation numbers and the word oxidised or reduced. Naming the oxidising agent means naming the species that is reduced.<\/p>\n      <\/div>\n    <\/article>\n\n    <section class=\"ols-related-card\">\n      <h2>Related Topic 8 Pages<\/h2>\n      <p>Use these pages to connect redox chemistry with the other parts of Topic 8 and with the core practicals.<\/p>\n\n      <div class=\"ols-related-grid\">\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8b-groups-1-and-2\/\">Topic 8B Groups 1 and 2<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8c-group-7\/\">Topic 8C Group 7<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/\">Topic 8 Overview<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-3-concentration-of-hcl-by-titration\/\">CP 3 Concentration of HCl by Titration<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-4-preparation-of-a-standard-solution\/\">CP 4 Preparation of a Standard Solution<\/a>\n        <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/core-practicals\/cp-8-analysis-of-inorganic-and-organic-unknowns\/\">CP 8 Analysis of Inorganic and Organic Unknowns<\/a>\n      <\/div>\n    <\/section>\n\n    <section class=\"ols-attribution-card\">\n      <p><strong>Copyright notice:<\/strong> This revision page, including its written explanations, layout and teaching sequence, is produced for Online Learning System by Dr. Mohammed Al-Fatah. It is intended for student revision and may not be copied, redistributed or republished without permission.<\/p>\n    <\/section>\n\n    <script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@graph\": [\n    {\n      \"@type\": \"WebPage\",\n      \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/#webpage\",\n      \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel-international\/topic-8-redox-chemistry-and-groups-1-2-and-7\/8a-redox-chemistry\/\",\n      \"name\": \"Topic 8A Redox Chemistry | Edexcel International A Level Chemistry\",\n      \"description\": \"Edexcel International A Level Chemistry Topic 8A Redox Chemistry landing page: oxidation numbers, electron transfer and half-equations, disproportionation, redox classification.\",\n      \"inLanguage\": \"en-GB\",\n   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