{"id":4847,"date":"2026-06-03T06:24:43","date_gmt":"2026-06-03T05:24:43","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/"},"modified":"2026-10-14T09:07:20","modified_gmt":"2026-10-14T08:07:20","slug":"kmno4","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/","title":{"rendered":"KMnO4"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-alkene-kmno4-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      --green: #3f8f46;\n      --red: #d94b2b;\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\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n    .ols-reaction-sublist {\n      list-style: none;\n      margin: 10px 0 0;\n      padding: 0 0 0 14px;\n      display: grid;\n      gap: 7px;\n      border-left: 2px solid rgba(37, 99, 235, 0.18);\n    }\n\n    .ols-reaction-sublist li {\n      font-size: 14px;\n      border-radius: 12px;\n    }\n\n    .ols-reaction-sublist li.active {\n      padding: 0;\n      background: #ffffff;\n      color: var(--blue);\n      font-weight: 700;\n      box-shadow: inset 3px 0 0 var(--blue);\n    }\n\n    .ols-reaction-sublist li.active a {\n      color: var(--blue);\n      font-weight: 700;\n      background: #ffffff;\n      padding-left: 13px;\n    }\n\n    .ols-reaction-sublist li:not(.active) {\n      padding: 0;\n    }\n\n    .ols-reaction-sublist a {\n      padding: 9px 10px;\n      border-radius: 12px;\n      font-size: 14px;\n    }\n\n    .ols-main {\n      min-width: 0;\n      max-width: 970px;\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-h5p-card,\n    .ols-related-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: 14px;\n      padding-top: 22px;\n      border-top: 1px solid var(--border);\n    }\n\n\n\n\n    .ols-note-card.soft {\n      background: linear-gradient(135deg, #ffffff 0%, var(--soft-red) 100%);\n    }\n\n    .ols-note-card.purple {\n      background: linear-gradient(135deg, #ffffff 0%, var(--soft-purple) 100%);\n    }\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-h5p-card 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-h5p-card h2,\n    .ols-related-card h2 {\n      margin-bottom: 14px;\n    }\n\n    .ols-note-card p,\n    .ols-note-card li {\n      font-size: clamp(15px, 1.25vw, 17px);\n      line-height: 1.65;\n      font-weight: 300;\n      color: var(--body-text);\n    }\n\n    .ols-h5p-card p,\n    .ols-related-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-h5p-card strong,\n    .ols-related-card strong {\n      font-weight: 700;\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: 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-reaction-summary {\n      display: grid;\n      grid-template-columns: repeat(2, minmax(0, 1fr));\n      gap: 14px;\n      margin-top: 20px;\n    }\n\n    .ols-summary-item {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 18px;\n      padding: 16px;\n      box-shadow: var(--inner-shadow);\n    }\n\n    .ols-summary-item span {\n      display: block;\n      font-size: 13px;\n      font-weight: 700;\n      color: var(--grey-text);\n      margin-bottom: 6px;\n    }\n\n    .ols-summary-item strong {\n      display: block;\n      font-size: 16px;\n      line-height: 1.45;\n      color: var(--navy);\n    }\n\n    .ols-figure-card {\n      margin: 26px 0 4px;\n      border: 1px solid var(--border);\n      border-radius: 26px;\n      overflow: hidden;\n      background: #ffffff;\n      box-shadow: var(--inner-shadow);\n    }\n\n    .ols-figure-image {\n      width: 100%;\n      min-height: 260px;\n      display: flex;\n      align-items: center;\n      justify-content: center;\n      background: #ffffff;\n      padding: 20px;\n    }\n\n    .ols-figure-image img {\n      max-width: 100%;\n      height: auto;\n      display: block;\n    }\n\n    .ols-figure-caption {\n      padding: 22px 26px 24px;\n      background: linear-gradient(135deg, #ffffff, #f8fbff);\n    }\n\n    .ols-figure-caption p {\n      margin: 0;\n      color: #5f6b85;\n      font-size: clamp(16px, 1.4vw, 19px);\n      line-height: 1.65;\n      font-weight: 300;\n      font-style: italic;\n    }\n\n    .ols-mechanism-steps {\n      display: grid;\n      gap: 14px;\n      margin-top: 20px;\n    }\n\n    .ols-step-card {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 20px;\n      padding: 18px 20px;\n      box-shadow: var(--inner-shadow);\n    }\n\n    .ols-step-card h3 {\n      margin: 0 0 8px;\n      font-size: 21px;\n      line-height: 1.25;\n      color: var(--navy);\n    }\n\n    .ols-step-card p {\n      margin: 0;\n    }\n\n    .ols-definition-box {\n      background: linear-gradient(135deg, #ffffff, var(--soft-purple));\n      border: 2px dashed rgba(122, 62, 157, 0.35);\n      border-radius: 24px;\n      padding: 26px;\n      margin-top: 22px;\n      display: grid;\n      grid-template-columns: 1fr;\n      gap: 16px;\n      align-items: center;\n    }\n\n.ols-definition-circle {\n  width: 105px;\n  height: 105px;\n  border-radius: 50%;\n  background: linear-gradient(135deg, #9b59b6, #6f3d96);\n  color: white;\n  display: flex;\n  align-items: center;\n  justify-content: center;\n  font-size: 26px;\n  font-weight: 800;\n  text-align: center;\n  margin: 0 auto;\n  line-height: 1;\n  white-space: nowrap;\n}\n\n.ols-definition-circle sub {\n  font-size: 0.6em;\n  vertical-align: -0.25em;\n  line-height: 0;\n}\n\n    .ols-h5p-card {\n      background: linear-gradient(135deg, #ffffff 0%, #f7f0ff 100%);\n    }\n\n    .ols-h5p-frame {\n      margin-top: 22px;\n      padding: 18px;\n      border-radius: 24px;\n      background: #ffffff;\n      border: 1px solid var(--border);\n      box-shadow: inset 0 0 0 1px rgba(28, 36, 75, 0.03);\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;\n    }\n\n    .ols-related-item:hover {\n      transform: translateY(-2px);\n      box-shadow: 0 10px 22px rgba(28, 36, 75, 0.08);\n    }\n\n    .ols-unlock {\n      background: linear-gradient(135deg, var(--navy), #0f4fa8);\n      border-radius: 30px;\n      padding: 36px;\n      color: #ffffff;\n      box-shadow: var(--shadow);\n      text-align: center;\n      margin: 30px 0 24px;\n    }\n\n    .ols-unlock h2 {\n      margin: 0 0 12px;\n      font-size: clamp(30px, 4vw, 46px);\n      line-height: 1.15;\n      font-weight: 800;\n      color: #ffffff;\n      text-align: center;\n    }\n\n    .ols-unlock p {\n      margin: 0 auto 24px;\n      max-width: 700px;\n      font-size: 20px;\n      line-height: 1.6;\n      font-weight: 300;\n      text-align: center;\n      color: #ffffff;\n    }\n\n    .ols-cta-button {\n      display: inline-flex;\n      align-items: center;\n      justify-content: center;\n      padding: 14px 26px;\n      border-radius: 999px;\n      background: #ffffff;\n      color: var(--navy);\n      text-decoration: none;\n      font-weight: 700;\n      transition: background 0.2s ease, color 0.2s ease, transform 0.2s ease;\n    }\n\n    .ols-cta-button:hover {\n      background: #f8fbff;\n      color: var(--blue);\n      transform: translateY(-1px);\n    }\n\n    @media (max-width: 1050px) {\n\n\n\n      .ols-reaction-sublist {\n        grid-template-columns: 1fr;\n      }\n\n      .ols-main {\n        max-width: none;\n      }\n\n      .ols-related-grid {\n        grid-template-columns: repeat(2, minmax(0, 1fr));\n      }\n    }\n\n    @media (max-width: 760px) {\n\n      .ols-title-card,\n      .ols-note-card,\n      .ols-h5p-card,\n      .ols-related-card,\n      .ols-unlock {\n        padding: 24px 18px;\n        border-radius: 22px;\n      }\n\n      .ols-note-title {\n        align-items: flex-start;\n      }\n\n      .ols-figure-card {\n        border-radius: 22px;\n      }\n\n      .ols-figure-image {\n        min-height: 210px;\n        padding: 14px;\n      }\n\n      .ols-figure-caption {\n        padding: 18px;\n      }\n\n      .ols-topic-list,\n      .ols-related-grid,\n      .ols-reaction-summary {\n        grid-template-columns: 1fr;\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    .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    .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    .ols-author-content { min-width: 0; }\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    .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    .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    .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    }\n    .ols-linkedin-icon { width: 18px; height: 18px; display: block; flex-shrink: 0; }\n    .ols-attribution-card {\n      background: linear-gradient(135deg, #ffffff, #f8fbff);\n      border: 1px solid rgba(28, 36, 75, 0.14);\n      border-radius: 28px;\n      box-shadow: 0 18px 45px rgba(28, 36, 75, 0.10);\n      padding: 34px;\n      margin-bottom: 24px;\n      overflow: hidden;\n      box-sizing: border-box;\n    }\n    .ols-attribution-card p {\n      margin: 0;\n      font-size: 14px;\n      line-height: 1.65;\n      font-weight: 300;\n      color: #667085;\n    }\n    .ols-attribution-card strong { font-weight: 700; color: #1C244B; }\n\n\n    \/* OLS non-clipping hover zoom and fullscreen image system *\/\n    .ols-alkene-kmno4-page,\n    .ols-alkene-kmno4-page .ols-main,\n    .ols-alkene-kmno4-page .ols-title-card,\n    .ols-alkene-kmno4-page .ols-note-card,\n    .ols-alkene-kmno4-page .ols-figure-card,\n    .ols-alkene-kmno4-page .ols-figure-image,\n    .ols-alkene-kmno4-page .ols-image-fullscreen-button {\n      overflow: visible !important;\n    }\n\n    .ols-alkene-kmno4-page .ols-figure-card {\n      position: relative;\n      z-index: 1;\n    }\n\n    .ols-alkene-kmno4-page .ols-figure-image {\n      position: relative;\n      border-radius: 26px 26px 0 0;\n    }\n\n    .ols-alkene-kmno4-page .ols-image-fullscreen-button {\n      display: inline-block;\n      max-width: 100%;\n      line-height: 0;\n      position: relative;\n      z-index: 2;\n      cursor: zoom-in;\n      padding: 0;\n      margin: 0;\n      border: 0;\n      background: transparent;\n      font: inherit;\n      appearance: none;\n      -webkit-appearance: none;\n    }\n\n    .ols-alkene-kmno4-page .ols-hover-zoom-img {\n      max-width: 100%;\n      height: auto;\n      display: block;\n      position: relative;\n      z-index: 2;\n      transform-origin: center center;\n      transition: transform 0.28s ease, box-shadow 0.28s ease, border-radius 0.28s ease;\n      cursor: zoom-in;\n    }\n\n    .ols-alkene-kmno4-page .ols-image-fullscreen-button:hover,\n    .ols-alkene-kmno4-page .ols-image-fullscreen-button:focus-visible {\n      z-index: 80;\n    }\n\n    .ols-alkene-kmno4-page .ols-image-fullscreen-button:hover .ols-hover-zoom-img,\n    .ols-alkene-kmno4-page .ols-image-fullscreen-button:focus-visible .ols-hover-zoom-img {\n      transform: scale(1.5);\n      box-shadow: 0 28px 70px rgba(28, 36, 75, 0.24);\n      border-radius: 18px;\n      z-index: 90;\n    }\n\n    .ols-alkene-kmno4-page .ols-lightbox-overlay {\n      position: fixed;\n      inset: 0;\n      z-index: 999999;\n      display: none;\n      align-items: center;\n      justify-content: center;\n      padding: 28px;\n      background: rgba(8, 13, 30, 0.88);\n    }\n\n    .ols-alkene-kmno4-page .ols-lightbox-overlay.is-open {\n      display: flex;\n    }\n\n    .ols-alkene-kmno4-page .ols-lightbox-img {\n      max-width: min(96vw, 1400px);\n      max-height: 92vh;\n      width: auto;\n      height: auto;\n      object-fit: contain;\n      border-radius: 18px;\n      background: #ffffff;\n      box-shadow: 0 30px 90px rgba(0, 0, 0, 0.42);\n    }\n\n    .ols-alkene-kmno4-page .ols-lightbox-close {\n      position: fixed;\n      top: 18px;\n      right: 22px;\n      width: 46px;\n      height: 46px;\n      border: 0;\n      border-radius: 999px;\n      background: #ffffff;\n      color: #1C244B;\n      font-size: 30px;\n      line-height: 1;\n      font-weight: 700;\n      cursor: pointer;\n      box-shadow: 0 12px 30px rgba(0, 0, 0, 0.25);\n    }\n\n    @media (max-width: 760px) {\n      .ols-alkene-kmno4-page .ols-image-fullscreen-button:hover .ols-hover-zoom-img,\n      .ols-alkene-kmno4-page .ols-image-fullscreen-button:focus-visible .ols-hover-zoom-img {\n        transform: none;\n        box-shadow: none;\n        border-radius: 0;\n      }\n    }\n\n    \/* OLS fixed lightbox system: scoped and safe if WordPress moves the overlay *\/\n    .ols-lightbox-overlay.ols-alkene-kmno4-page-lb {\n      position: fixed !important;\n      inset: 0 !important;\n      z-index: 999999 !important;\n      display: none !important;\n      align-items: center !important;\n      justify-content: center !important;\n      padding: 28px !important;\n      background: rgba(8, 13, 30, 0.88) !important;\n    }\n\n    .ols-lightbox-overlay.ols-alkene-kmno4-page-lb.is-open {\n      display: flex !important;\n    }\n\n    .ols-lightbox-overlay.ols-alkene-kmno4-page-lb .ols-lightbox-img {\n      max-width: min(96vw, 1400px) !important;\n      max-height: 92vh !important;\n      width: auto !important;\n      height: auto !important;\n      object-fit: contain !important;\n      border-radius: 18px !important;\n      background: #ffffff !important;\n      box-shadow: 0 30px 90px rgba(0, 0, 0, 0.42) !important;\n      display: block !important;\n    }\n\n    .ols-lightbox-overlay.ols-alkene-kmno4-page-lb .ols-lightbox-close {\n      position: fixed !important;\n      top: 18px !important;\n      right: 22px !important;\n      width: 46px !important;\n      height: 46px !important;\n      display: flex !important;\n      align-items: center !important;\n      justify-content: center !important;\n      border: 0 !important;\n      border-radius: 999px !important;\n      background: #ffffff !important;\n      color: #1C244B !important;\n      font-size: 30px !important;\n      line-height: 1 !important;\n      font-weight: 700 !important;\n      cursor: pointer !important;\n      box-shadow: 0 12px 30px rgba(0, 0, 0, 0.25) !important;\n      padding: 0 !important;\n      margin: 0 !important;\n    }\n\n\n  \n.ols-faq-card,\n    .ols-quicksnap-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.ols-faq-card h2,\n    .ols-quicksnap-card h2,\n    .ols-infographic-title {\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.ols-faq-card h2,\n    .ols-quicksnap-card h2 {\n      margin-bottom: 14px;\n    }\n.ols-faq-card p,\n    .ols-quicksnap-card p {\n      font-size: clamp(15px, 1.25vw, 17px);\n      line-height: 1.65;\n      font-weight: 300;\n      color: var(--body-text);\n    }\n.ols-faq-card strong,\n    .ols-quicksnap-card strong {\n      font-weight: 700;\n      color: var(--navy);\n    }\n.ols-faq-list {\n      display: grid;\n      gap: 14px;\n      margin-top: 18px;\n    }\n.ols-faq-item {\n      background: #ffffff;\n      border: 1px solid var(--border);\n      border-radius: 18px;\n      padding: 18px 20px;\n      box-shadow: var(--inner-shadow);\n    }\n.ols-faq-item h3 {\n      margin: 0 0 8px;\n      font-size: 20px;\n      line-height: 1.3;\n      color: var(--navy);\n    }\n.ols-faq-item p {\n      margin: 0;\n      font-size: 16px;\n      line-height: 1.65;\n      color: var(--body-text);\n    }\n.ols-faq-card,\n      .ols-quicksnap-card,\n      .ols-attribution-card {\n        padding: 24px 18px;\n        border-radius: 22px;\n      }\n<\/style>\n\n    <aside class=\"ols-sidebar\">\r\n  <div class=\"ols-sidebar-header\">\r\n    <h3>Revision Notes<\/h3>\r\n    <p>A Level Chemistry<\/p>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Topic 6 Organic Chemistry I<\/h4>\r\n\r\n    <ul class=\"ols-topic-list\">\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/\">Introduction to Organic Chemistry<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/iupac-rules\/\">IUPAC Rules<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/alkene\/\">Alkene<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/alcohol\/\">Alcohol<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/halogenoalkanes\/\">Halogenoalkanes<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/aldehyde\/\">Aldehyde<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/ketone\/\">Ketone<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/carboxylic-acid\/\">Carboxylic Acid<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/ester\/\">Ester<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/introduction-to-organic-chemistry\/isomerism\/\">Isomerism<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/\">Alkanes<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/crude-oil\/\">Alkanes from Crude Oil<\/a>\r\n\r\n            <ul class=\"ols-subtopic-list\">\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/crude-oil\/fractional-distillation\/\">Fractional Distillation<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/crude-oil\/cracking\/\">Cracking<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/crude-oil\/reforming\/\">Reforming<\/a>\r\n              <\/li>\r\n            <\/ul>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/\">Alkanes as Fuel<\/a>\r\n\r\n            <ul class=\"ols-subtopic-list\">\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/combustion\/\">Combustion<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/oxides-of-sulfur\/\">Oxides of Sulfur<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/oxides-of-nitrogen\/\">Oxides of Nitrogen<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/fuel\/catalytic-converter\/\">Catalytic Converter<\/a>\r\n              <\/li>\r\n            <\/ul>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/alternative-fuel\/\">Alternative Fuel<\/a>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/\">Reactions of Alkanes<\/a>\r\n\r\n            <ul class=\"ols-subtopic-list\">\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/free-radical-substitution\/\">Free Radical Substitution<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/initiation\/\">Initiation<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/propagation\/\">Propagation<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/termination\/\">Termination<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkanes\/reactions\/further-substitution\/\">Further Substitution<\/a>\r\n              <\/li>\r\n            <\/ul>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/\">Alkenes<\/a>\r\n\r\n        <ul class=\"ols-subtopic-list\">\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/alkene-bonding\/\">Alkene Bonding<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/geometric-isomerism\/\">Geometric Isomerism<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/electrophilic-addition-mechanism\/\">Electrophilic Addition Mechanism<\/a>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/\">Reactions of Alkenes<\/a>\r\n\r\n            <ul class=\"ols-subtopic-list\">\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/halogens\/\">Halogens<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/hydrogen-halide\/\">Hydrogen Halide<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/bromine-water\/\">Bromine Water<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/hydrogen\/\">Hydrogen<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/steam\/\">Steam<\/a>\r\n              <\/li>\r\n              <li>\r\n                <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/\">KMnO4<\/a>\r\n              <\/li>\r\n            <\/ul>\r\n          <\/li>\r\n\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/polymerisation-reactions\/\">Polymerisation Reactions<\/a>\r\n          <\/li>\r\n          <li>\r\n            <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/polymer-waste\/\">Polymer Waste<\/a>\r\n          <\/li>\r\n        <\/ul>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/halogenoalkanes\/\">Halogenoalkanes<\/a>\r\n      <\/li>\r\n\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alcohols\/\">Alcohols<\/a>\r\n      <\/li>\r\n\r\n    <\/ul>\r\n  <\/div>\r\n\r\n  <div class=\"ols-topic-group\">\r\n    <h4>Next Topics<\/h4>\r\n\r\n    <ul class=\"ols-topic-list\">\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-7-modern-analytical-techniques-i\/\">Topic 7 Modern Analytical Techniques I<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-5-formulae-equations-and-amounts-of-substance\/\">Topic 5 Formulae, Equations &amp; Amounts<\/a>\r\n      <\/li>\r\n      <li>\r\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-4-inorganic-chemistry-and-the-periodic-table\/\">Topic 4 Inorganic Chemistry &amp; The Periodic Table<\/a>\r\n      <\/li>\r\n    <\/ul>\r\n  <\/div>\r\n<\/aside>\r\n\r\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    sidebar.querySelectorAll('.active, .active-main, .parent-active').forEach(function(item) {\r\n      item.classList.remove('active', 'active-main', 'parent-active');\r\n    });\r\n\r\n    sidebar.querySelectorAll('a[data-ols-disabled-parent=\"1\"], a[aria-current]').forEach(function(a) {\r\n      a.removeAttribute('aria-current');\r\n      a.removeAttribute('tabindex');\r\n      a.removeAttribute('data-ols-disabled-parent');\r\n    });\r\n\r\n    links.forEach(function(a) {\r\n      try {\r\n        var href = a.getAttribute('href');\r\n        if (!href || href === '#' || href.charAt(0) === '#') return;\r\n        var linkPath = normalisePath(new URL(href, window.location.origin).pathname);\r\n        if (!linkPath) return;\r\n        if (currentPath === linkPath || currentPath.indexOf(linkPath + '\/') === 0) {\r\n          if (linkPath.length > matchedLength) {\r\n            matched = a;\r\n            matchedLength = linkPath.length;\r\n          }\r\n        }\r\n      } catch(e) {}\r\n    });\r\n\r\n    if (matched) {\r\n      var matchedLi = matched.closest('li');\r\n      var parentSub = matched.closest('.ols-subtopic-list');\r\n\r\n      if (parentSub) {\r\n        if (matchedLi) {\r\n          matchedLi.classList.add('active');\r\n          matched.setAttribute('aria-current', 'page');\r\n        }\r\n\r\n        var parentLi = parentSub.closest('li');\r\n        while (parentLi) {\r\n          parentLi.classList.add('parent-active', 'active-main');\r\n\r\n          var parentLink = parentLi.querySelector(':scope > a');\r\n          if (parentLink) {\r\n            parentLink.setAttribute('aria-current', 'true');\r\n            parentLink.setAttribute('tabindex', '-1');\r\n            parentLink.setAttribute('data-ols-disabled-parent', '1');\r\n          }\r\n\r\n          var higherSub = parentLi.parentElement.closest('.ols-subtopic-list');\r\n          parentLi = higherSub ? higherSub.closest('li') : null;\r\n        }\r\n      } else {\r\n        if (matchedLi) {\r\n          matchedLi.classList.add('parent-active', '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>\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\/\">Edexcel<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/\">Topic 6 Organic Chemistry I<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/\">Alkenes<\/a> \/\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/\">Reactions of Alkenes<\/a> \/\n        <span>KMnO<sub>4<\/sub><\/span>\n      <\/nav>\n\n      <header class=\"ols-title-card\">\n        <h1>Reactions of Alkenes with KMnO<sub>4<\/sub><\/h1>\n        <p class=\"ols-page-intro\">A concise revision guide to the oxidation of alkenes using potassium manganate(VII), including the formation of diols, the purple to colourless observation and how this reaction can be used as a test for the alkene functional group.<\/p>\n\n        <div class=\"ols-badges\">\n          <div class=\"ols-badge\">Paper 2<\/div>\n          <div class=\"ols-badge\">Topic 6: Organic Chemistry I<\/div>\n          <div class=\"ols-badge\">9CH0\/02<\/div>\n        <\/div>\n      <\/header>\n\n      \n<section class=\"ols-h5p-card ols-h5p-inline ols-h5p-recap\">\n<span class=\"ols-h5p-kicker\">Before you start<\/span>\n<h2>GCSE Recap: Saturated, Unsaturated and a Positive Test<\/h2>\n<p>Before you start, check the GCSE ideas this page builds on: what makes a hydrocarbon unsaturated, and what a positive test looks like.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-content\" data-content-id=\"749\"><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card soft\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">1<\/div>\n          <h2>The Overall Reaction<\/h2>\n        <\/div>\n\n        <p>Alkenes react with <strong>KMnO<sub>4<\/sub><\/strong>, potassium manganate(VII), in <strong>acidified solution<\/strong> to form <strong>diols<\/strong>.<\/p>\n        <p>A <strong>diol<\/strong> is an organic compound containing two alcohol, <strong>-OH<\/strong>, groups. In this reaction, the C=C double bond opens and an <strong>-OH<\/strong> group is added to each carbon atom from the original double bond.<\/p>\n        <p>For example, <strong>propene<\/strong> is oxidised to form <strong>propane-1,2-diol<\/strong>.<\/p>\n\n        <div class=\"ols-reaction-summary\">\n          <div class=\"ols-summary-item\"><span>Functional group change<\/span><strong>Alkene \u2192 diol<\/strong><\/div>\n          <div class=\"ols-summary-item\"><span>Reagent<\/span><strong>KMnO<sub>4<\/sub> in acidified solution<\/strong><\/div>\n          <div class=\"ols-summary-item\"><span>Product from propene<\/span><strong>Propane-1,2-diol<\/strong><\/div>\n          <div class=\"ols-summary-item\"><span>Type of reaction<\/span><strong>Oxidation<\/strong><\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Key idea:<\/strong> KMnO<sub>4<\/sub> oxidises the alkene functional group, converting the C=C double bond into a diol.<\/p>\n        <\/div>\n\n        <div class=\"ols-figure-card\">\n          <div class=\"ols-figure-image\">\n            <a\n              class=\"ols-image-fullscreen-button ols-lightbox-trigger\"\n              href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t5-cd-09-propenediol.svg\"\n              aria-label=\"View image fullscreen\"\n              data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/skel-35-propene-kmno4-diol.svg\"\n              data-fullscreen-alt=\"Oxidation of propene with cold, dilute acidified potassium manganate(VII) to give propane-1,2-diol\"\n            >\n              <img decoding=\"async\"\n                class=\"ols-hover-zoom-img\"\n                src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t5-cd-09-propenediol.svg\"\n                alt=\"Propene oxidised by cold dilute acidified manganate(VII) to propane-1,2-diol, the new OH groups highlighted\" width=\"1424\" height=\"756\"\n              >\n            <\/a>\n          <\/div>\n          <div class=\"ols-figure-caption\">\n            <p>The displayed reaction shows the alkene functional group in propene changing into a diol after oxidation with KMnO<sub>4<\/sub>.<\/p>\n          <\/div>\n        <\/div>\n      <\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Name the Diol<\/h2>\n<p>Apply the reaction to an alkene that this page does not use.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-48\" class=\"h5p-iframe\" data-content-id=\"48\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Alkene Oxidation MCQ: The Diol Formed from But-2-ene\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">2<\/div>\n          <h2>Conditions and Observation<\/h2>\n        <\/div>\n\n        <p>This reaction is carried out using <strong>acidified KMnO<sub>4<\/sub><\/strong> at <strong>room temperature<\/strong>.<\/p>\n        <p>The important observation is that the <strong>purple colour<\/strong> of the MnO<sub>4<\/sub><sup>&#8211;<\/sup> ion <strong>decolourises to colourless<\/strong>.<\/p>\n        <p>This colour change is useful because it provides a simple chemical test for the presence of the <strong>alkene functional group<\/strong>.<\/p>\n\n        <div class=\"ols-reaction-summary\">\n          <div class=\"ols-summary-item\"><span>Condition<\/span><strong>Room temperature<\/strong><\/div>\n          <div class=\"ols-summary-item\"><span>Starting colour<\/span><strong>Purple<\/strong><\/div>\n          <div class=\"ols-summary-item\"><span>Final colour<\/span><strong>Colourless<\/strong><\/div>\n          <div class=\"ols-summary-item\"><span>Ion responsible<\/span><strong>MnO<sub>4<\/sub><sup>&#8211;<\/sup><\/strong><\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Exam focus:<\/strong> State the full observation as purple to colourless. Do not write only \u201cgoes clear\u201d.<\/p>\n        <\/div>\n      <\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Two Unlabelled Bottles<\/h2>\n<p>Drag the words into place to complete the account of the two tests.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-46\" class=\"h5p-iframe\" data-content-id=\"46\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Alkene Oxidation Drag: Identifying Two Unlabelled Hydrocarbons\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card purple\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">3<\/div>\n          <h2>Why It Tests for Alkenes<\/h2>\n        <\/div>\n\n        <p>The reaction can be used as a test for alkenes because alkenes contain a <strong>C=C double bond<\/strong> that can be oxidised under these conditions.<\/p>\n        <p>Alkanes do not contain a carbon-carbon double bond. They are saturated hydrocarbons, so they do not react in the same way with acidified KMnO<sub>4<\/sub> at room temperature.<\/p>\n        <p>Therefore, an alkene gives the purple to colourless change, but an alkane would show <strong>no colour change<\/strong>.<\/p>\n\n        <div class=\"ols-definition-box\">\n          <div class=\"ols-definition-circle\">Diol<\/div>\n          <p><strong>Diol:<\/strong> An organic compound containing two alcohol, <strong>-OH<\/strong>, groups. In this alkene oxidation reaction, the two -OH groups form on the two carbon atoms from the original C=C double bond.<\/p>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Remember:<\/strong> The test depends on oxidation of the alkene double bond, not substitution or hydrogenation.<\/p>\n        <\/div>\n      <div class=\"ols-figure-card ols-zoom-pop\">\n<div class=\"ols-figure-image\">\n<a class=\"ols-image-fullscreen-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t5-img-11-twotests.jpg\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open image fullscreen\">\n<img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t5-img-11-twotests.jpg\" alt=\"Bromine water and acidified manganate(VII) tests side by side for an alkene and an alkane\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t5-img-11-twotests.jpg\">\n<\/a>\n<\/div>\n<div class=\"ols-figure-caption\"><p>Both tests decolourise with an alkene: bromine water from orange, manganate(VII) from purple.<\/p><\/div>\n<\/div>\n<\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Which Samples React?<\/h2>\n<p>Click every hydrocarbon that makes the purple colour fade.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-47\" class=\"h5p-iframe\" data-content-id=\"47\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Alkene Oxidation Mark the Words: Which Samples Make the Purple Colour Fade\"><\/iframe><\/div><\/div>\n<\/section>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: The Limits of the Test<\/h2>\n<p>Write a short explanation, then compare it with the mark points and the model answer.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-49\" class=\"h5p-iframe\" data-content-id=\"49\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Alkene Oxidation Explain: What the Test Can and Cannot Tell You\"><\/iframe><\/div><\/div>\n<\/section>\n\n      <article class=\"ols-note-card soft\">\n        <div class=\"ols-note-title\">\n          <div class=\"ols-note-icon\">4<\/div>\n          <h2>Common Exam Mistakes<\/h2>\n        <\/div>\n\n        <p>Students often lose marks by forgetting that the product is a <strong>diol<\/strong>, not a single alcohol.<\/p>\n        <p>Another common error is to describe the reaction as addition only. The expected reaction type here is <strong>oxidation<\/strong>.<\/p>\n        <p>For observation questions, the safest answer should include both the starting colour and the final colour.<\/p>\n\n        <div class=\"ols-reaction-summary\">\n          <div class=\"ols-summary-item\"><span>Do say<\/span><strong>Purple MnO<sub>4<\/sub><sup>&#8211;<\/sup> decolourises to colourless.<\/strong><\/div>\n          <div class=\"ols-summary-item\"><span>Do not say only<\/span><strong>It goes clear.<\/strong><\/div>\n          <div class=\"ols-summary-item\"><span>Product type<\/span><strong>Diol, not just alcohol.<\/strong><\/div>\n          <div class=\"ols-summary-item\"><span>Reaction type<\/span><strong>Oxidation.<\/strong><\/div>\n        <\/div>\n\n        <div class=\"ols-key-box\">\n          <p><strong>Exam focus:<\/strong> Link the colour change to the reaction of MnO<sub>4<\/sub><sup>&#8211;<\/sup> with the alkene C=C double bond.<\/p>\n        <\/div>\n      <div class=\"ols-figure-card ols-zoom-pop\">\n<div class=\"ols-figure-image\">\n<a class=\"ols-image-fullscreen-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t5-img-07-brwatertest.jpg\" target=\"_blank\" rel=\"noopener\" aria-label=\"Open image fullscreen\">\n<img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t5-img-07-brwatertest.jpg\" alt=\"Bromine water test: alkene turns orange bromine water colourless, alkane leaves it orange, with the exam wording\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/10\/t5-img-07-brwatertest.jpg\">\n<\/a>\n<\/div>\n<div class=\"ols-figure-caption\"><p>For the bromine water test too, give both colours: orange to colourless, never just &#8220;clear&#8221;.<\/p><\/div>\n<\/div>\n<\/article>\n<section class=\"ols-h5p-card ols-h5p-inline\">\n<span class=\"ols-h5p-kicker\">Check your understanding<\/span>\n<h2>Quick Check: Oxidising an Alkene from Start to Finish<\/h2>\n<p>Each round covers one part of the page, from the product to the conditions. Choose the one accurate statement.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-1275\" class=\"h5p-iframe\" data-content-id=\"1275\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Alkene Oxidation Summary: Pent-2-ene and Manganate(VII)\"><\/iframe><\/div><\/div>\n<\/section>\n\n      \n\n      <section class=\"ols-faq-card\">\n        <h2>FAQs<\/h2>\n        <p>These questions cover the manganate(VII) points that cost marks.<\/p>\n        <div class=\"ols-faq-list\">\n          <div class=\"ols-faq-item\">\n            <h3>What is the colour change with an alkene?<\/h3>\n            <p>Purple to colourless, as the MnO<sub>4<\/sub><sup>&#8211;<\/sup> ion is reduced. Give both colours.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>What does ethene give with cold, dilute acidified KMnO<sub>4<\/sub>?<\/h3>\n            <p>Ethane-1,2-diol, HOCH<sub>2<\/sub>CH<sub>2<\/sub>OH. One -OH group adds to each carbon of the double bond.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>Is this reaction addition or oxidation?<\/h3>\n            <p>Name it oxidation. The alkene gains oxygen, and the manganate(VII) is the oxidising agent.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>Why is bromine water the more common alkene test?<\/h3>\n            <p>Both tests work, but manganate(VII) also oxidises other groups, such as aldehydes and some alcohols, so a colour change is less specific.<\/p>\n          <\/div>\n          <div class=\"ols-faq-item\">\n            <h3>What does the diol product have in common with ethanol?<\/h3>\n            <p>Both are alcohols. A diol has two -OH groups, on adjacent carbons here.<\/p>\n          <\/div>\n        <\/div>\n      <\/section>\n\n      <!-- author card (moved to the end, 10 Oct 2026) -->\n      <div class=\"ols-author\">\n\n    <img decoding=\"async\"\n      class=\"ols-author-avatar-img\"\n      src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\"\n      alt=\"Dr. Mohammed Al-Fatah\"\n    >\n\n    <div class=\"ols-author-content\">\n\n      <h2 class=\"ols-author-title\">\n        Written by: Dr. Mohammed Al-Fatah\n      <\/h2>\n\n      <p class=\"ols-author-description\">\n        Chemistry specialist revision notes for A Level Chemistry.\n      <\/p>\n\n      <a\n        class=\"ols-linkedin-pill\"\n        href=\"https:\/\/www.linkedin.com\/in\/doctormohammedfatah\/\"\n        target=\"_blank\"\n        rel=\"noopener noreferrer\"\n      >\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\"\/>\n        <\/svg>\n        View LinkedIn Profile\n      <\/a>\n\n    <\/div>\n\n  <\/div>\n\n\n<section class=\"ols-related-card\">\n        <h2>Related Alkene Revision Notes<\/h2>\n        <p>Continue through Topic 6 by linking oxidation with the other addition reactions of alkenes.<\/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\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/steam\/\">Steam<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/hydrogen\/\">Hydrogen<\/a>\n          <a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/bromine-water\/\">Bromine Water<\/a>\n        <\/div>\n      <\/section>\n\n      <section class=\"ols-attribution-card ols-attr-std\" aria-label=\"Copyright notice\">\n<style id=\"ols-attribution-card-css\">.ols-attribution-card.ols-attr-std{background:linear-gradient(135deg,#ffffff,#f8fbff);border:1px solid rgba(28,36,75,0.14);border-radius:28px;box-shadow:0 18px 45px rgba(28,36,75,0.10);padding:34px;margin:24px 0;overflow:hidden;font-family:Poppins,Arial,sans-serif;box-sizing:border-box}.ols-attribution-card.ols-attr-std *{box-sizing:border-box}.ols-attribution-card.ols-attr-std p{margin:0;font-size:14px;line-height:1.65;font-weight:300;color:#667085}.ols-attribution-card.ols-attr-std strong{font-weight:700;color:#1C244B}@media (max-width:760px){.ols-attribution-card.ols-attr-std{padding:24px 18px;border-radius:22px}}<\/style>\n<p><strong>Copyright notice:<\/strong> This OLS revision content, including the explanations, layout, diagrams, tables and embedded learning structure, is authored for Online Learning System by Dr. Mohammed Al-Fatah. It may not be copied, reproduced, redistributed or adapted without written permission.<\/p>\n<\/section>\n\n      <div class=\"ols-lightbox-overlay ols-alkene-kmno4-page-lb\" role=\"dialog\" aria-modal=\"true\" aria-label=\"Image lightbox\">\n        <button class=\"ols-lightbox-close\" type=\"button\" aria-label=\"Close fullscreen image\">\u00d7<\/button>\n        <img decoding=\"async\" class=\"ols-lightbox-img\" src=\"\" alt=\"\">\n      <\/div>\n\n      <script>\n      (function(){\n        var wrap = document.querySelector('.ols-alkene-kmno4-page');\n        if (!wrap) { return; }\n\n        var overlay = document.querySelector('.ols-alkene-kmno4-page-lb');\n        if (!overlay) { return; }\n\n        var lbImg = overlay.querySelector('.ols-lightbox-img');\n        if (!lbImg) { return; }\n\n        var closeBtn = overlay.querySelector('.ols-lightbox-close');\n        var triggers = wrap.querySelectorAll('.ols-lightbox-trigger');\n\n        function openLightbox(trigger){\n          var img = trigger.querySelector('img');\n          var src = trigger.getAttribute('data-fullscreen-src');\n\n          if (!src) {\n            src = trigger.getAttribute('href');\n          }\n\n          if (!src) {\n            if (img) {\n              src = img.currentSrc || img.src;\n            }\n          }\n\n          var alt = trigger.getAttribute('data-fullscreen-alt');\n\n          if (!alt) {\n            if (img) {\n              alt = img.alt || '';\n            } else {\n              alt = '';\n            }\n          }\n\n          if (!src) { return; }\n\n          lbImg.src = src;\n          lbImg.alt = alt;\n          overlay.classList.add('is-open');\n          document.body.style.overflow = 'hidden';\n        }\n\n        function closeLightbox(){\n          overlay.classList.remove('is-open');\n          document.body.style.overflow = '';\n          lbImg.src = '';\n          lbImg.alt = '';\n        }\n\n        for (var i = 0; i < triggers.length; i++) {\n          triggers[i].addEventListener('click', function(event){\n            event.preventDefault();\n            event.stopPropagation();\n            openLightbox(this);\n          });\n        }\n\n        if (closeBtn) {\n          closeBtn.addEventListener('click', function(event){\n            event.preventDefault();\n            event.stopPropagation();\n            closeLightbox();\n          });\n        }\n\n        overlay.addEventListener('click', function(event){\n          if (event.target === overlay) {\n            closeLightbox();\n          }\n        });\n\n        document.addEventListener('keydown', function(event){\n          if (event.key === 'Escape') {\n            if (overlay.classList.contains('is-open')) {\n              closeLightbox();\n            }\n          }\n        });\n      })();\n      <\/script>\n\n      <\/main>\n\n<script type=\"application\/ld+json\">\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@graph\": [\n        {\n            \"@type\": \"Organization\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/#organization\",\n            \"name\": \"Online Learning System\",\n            \"url\": \"https:\/\/www.onlinelearningsystem.net\/\"\n        },\n        {\n            \"@type\": \"WebSite\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/#website\",\n            \"url\": \"https:\/\/www.onlinelearningsystem.net\/\",\n            \"name\": \"Online Learning System\",\n            \"publisher\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/#organization\"\n            }\n        },\n        {\n            \"@type\": \"WebPage\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/#webpage\",\n            \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/\",\n            \"name\": \"Reactions of Alkenes with KMnO4\",\n            \"headline\": \"Reactions of Alkenes with KMnO4\",\n            \"description\": \"Revise reactions of alkenes with KMnO4 for Edexcel A Level Chemistry, including oxidation, diol formation, purple to colourless observation and the test for C=C double bonds.\",\n            \"inLanguage\": \"en-GB\",\n            \"isPartOf\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/#website\"\n            },\n            \"publisher\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/#organization\"\n            },\n            \"author\": {\n                \"@type\": \"Person\",\n                \"name\": \"Dr. Mohammed Al-Fatah\"\n            },\n            \"primaryImageOfPage\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/#reaction-image\"\n            },\n            \"breadcrumb\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/#breadcrumb\"\n            }\n        },\n        {\n            \"@type\": \"BreadcrumbList\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/#breadcrumb\",\n            \"itemListElement\": [\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 1,\n                    \"name\": \"Revision Notes\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 2,\n                    \"name\": \"A Level Chemistry\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 3,\n                    \"name\": \"Edexcel\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 4,\n                    \"name\": \"Topic 6 Organic Chemistry I\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 5,\n                    \"name\": \"Alkenes\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 6,\n                    \"name\": \"Reactions of Alkenes\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/\"\n                },\n                {\n                    \"@type\": \"ListItem\",\n                    \"position\": 7,\n                    \"name\": \"KMnO4\",\n                    \"item\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/\"\n                }\n            ]\n        },\n        {\n            \"@type\": \"Course\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/#course\",\n            \"name\": \"Reactions of Alkenes with KMnO4\",\n            \"description\": \"Revision notes for Edexcel A Level Chemistry covering alkene oxidation with acidified potassium manganate(VII), diol formation and the purple to colourless alkene test.\",\n            \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/\",\n            \"provider\": {\n                \"@id\": \"https:\/\/www.onlinelearningsystem.net\/#organization\"\n            },\n            \"educationalLevel\": \"A Level\",\n            \"courseCode\": \"9CH0\/02\",\n            \"inLanguage\": \"en-GB\",\n            \"teaches\": [\n                \"Alkene oxidation\",\n                \"Acidified KMnO4\",\n                \"Potassium manganate(VII)\",\n                \"Diol formation\",\n                \"Purple to colourless observation\",\n                \"C=C double bond test\",\n                \"Propane-1,2-diol\"\n            ],\n            \"hasCourseInstance\": {\n                \"@type\": \"CourseInstance\",\n                \"courseMode\": \"online\",\n                \"courseWorkload\": \"Self-paced revision\"\n            }\n        },\n        {\n            \"@type\": \"ImageObject\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/#reaction-image\",\n            \"name\": \"Propene Oxidation to Propane-1,2-diol\",\n            \"description\": \"Displayed formula reaction showing propene oxidised to propane-1,2-diol using KMnO4.\",\n            \"contentUrl\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/skel-35-propene-kmno4-diol.svg\",\n            \"url\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/skel-35-propene-kmno4-diol.svg\"\n        },\n        {\n            \"@type\": \"FAQPage\",\n            \"@id\": \"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/edexcel\/topic-6-organic-chemistry-i\/alkenes\/reactions-of-alkenes\/kmno4\/#faq\",\n            \"mainEntity\": [\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"What is the colour change with an alkene?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"Purple to colourless, as the MnO4- ion is reduced. Give both colours.\"\n                    }\n                },\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"What does ethene give with cold, dilute acidified KMnO4?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"Ethane-1,2-diol, HOCH2CH2OH. One -OH group adds to each carbon of the double bond.\"\n                    }\n                },\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"Is this reaction addition or oxidation?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"Name it oxidation. The alkene gains oxygen, and the manganate(VII) is the oxidising agent.\"\n                    }\n                },\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"Why is bromine water the more common alkene test?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"Both tests work, but manganate(VII) also oxidises other groups, such as aldehydes and some alcohols, so a colour change is less specific.\"\n                    }\n                },\n                {\n                    \"@type\": \"Question\",\n                    \"name\": \"What does the diol product have in common with ethanol?\",\n                    \"acceptedAnswer\": {\n                        \"@type\": \"Answer\",\n                        \"text\": \"Both are alcohols. A diol has two -OH groups, on adjacent carbons here.\"\n                    }\n                }\n            ]\n        }\n    ]\n}\n<\/script>\n\n<\/section>\n\n","protected":false},"excerpt":{"rendered":"<p>Revision Notes \/ A Level Chemistry \/ Edexcel \/ Topic 6 Organic Chemistry I \/ Alkenes \/ Reactions of Alkenes \/ KMnO4 Reactions of Alkenes with KMnO4 A concise revision guide to the oxidation of alkenes using potassium manganate(VII), including the formation of diols, the purple to colourless observation and how this reaction can be [&hellip;]<\/p>\n","protected":false},"author":12,"featured_media":0,"parent":4841,"menu_order":5,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-4847","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4847","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=4847"}],"version-history":[{"count":0,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4847\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/pages\/4841"}],"wp:attachment":[{"href":"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-json\/wp\/v2\/media?parent=4847"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}