{"id":7169,"date":"2026-09-08T17:56:58","date_gmt":"2026-09-08T16:56:58","guid":{"rendered":"https:\/\/www.onlinelearningsystem.net\/xyz\/?page_id=7169"},"modified":"2026-09-25T09:31:13","modified_gmt":"2026-09-25T08:31:13","slug":"producing-alkenes","status":"publish","type":"page","link":"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/producing-alkenes\/","title":{"rendered":"Producing Alkenes"},"content":{"rendered":"\n<section class=\"ols-revision-page ols-alkene-hydrogen-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      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grid; gap: 12px; margin: 18px 0 0; padding: 0; list-style: none; }\n    .ols-quicksnap-list li { padding: 14px 16px; border-radius: 16px; background: #ffffff; border: 1px solid var(--border); box-shadow: var(--inner-shadow); font-size: 16px; line-height: 1.6; color: var(--body-text); overflow-wrap: anywhere; }\n<\/style>\n\n  <aside class=\"ols-sidebar\">\n  <div class=\"ols-sidebar-header\">\n    <h3>Revision Notes<\/h3>\n    <p>Cambridge International AS Level Chemistry<\/p>\n  <\/div>\n  <div class=\"ols-topic-group\">\n    <h4>14.2 Alkenes<\/h4>\n    <ul class=\"ols-topic-list\">\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/\">Part overview<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/producing-alkenes\/\">Producing Alkenes<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/electrophilic-addition-mechanism\/\">Electrophilic Addition Mechanism<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/markovnikov-addition\/\">Markovnikov Addition<\/a><\/li>\n      <li>\n        <a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/\">Reactions of Alkenes<\/a>\n        <ul class=\"ols-subtopic-list\">\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/hydrogen\/\">Hydrogen<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/halogens\/\">Halogens<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/bromine-water\/\">Bromine Water<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/hydrogen-halide\/\">Hydrogen Halide<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/steam\/\">Steam<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/kmno4\/\">KMnO4<\/a><\/li>\n          <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/oxidative-cleavage\/\">Oxidative Cleavage<\/a><\/li>\n        <\/ul>\n      <\/li>\n    <\/ul>\n  <\/div>\n  <div class=\"ols-topic-group\">\n    <h4>Other Topics<\/h4>\n    <ul class=\"ols-topic-list\">\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/\">Topic 14 overview<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkanes\/\">14.1 Alkanes<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-13-an-introduction-to-as-level-organic-chemistry\/\">Topic 13 Introduction to AS Organic Chemistry<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-20-polymerisation\/\">Topic 20 Polymerisation<\/a><\/li>\n      <li><a href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-15-halogen-compounds\/\">Topic 15 Halogen Compounds<\/a><\/li>\n    <\/ul>\n  <\/div>\n<\/aside>\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     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href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/\">Alkenes<\/a> \/\n<span>Producing Alkenes<\/span>\n<\/nav>\n<header class=\"ols-title-card\">\n<h1>Producing Alkenes<\/h1>\n<p class=\"ols-page-intro\">A concise revision guide to the three routes by which alkenes are produced for Cambridge International AS Level Chemistry: elimination of a hydrogen halide from a halogenoalkane, dehydration of an alcohol, and cracking of a longer-chain alkane.<\/p>\n<div class=\"ols-badges\"><div class=\"ols-badge\">AS Level<\/div>\n<div class=\"ols-badge\">Topic 14: Hydrocarbons<\/div>\n<div class=\"ols-badge\">9701 Papers 1 and 2<\/div><\/div>\n<div class=\"ols-author\">\n<img decoding=\"async\" alt=\"Dr. Mohammed Al-Fatah\" class=\"ols-author-avatar-img\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/05\/Author-Profile.jpeg\"\/>\n<div class=\"ols-author-content\">\n<h2 class=\"ols-author-title\">\n        Written by: Dr. Mohammed Al-Fatah\n      <\/h2>\n<p class=\"ols-author-description\">\n        Chemistry specialist revision notes for A Level Chemistry.\n      <\/p>\n<a class=\"ols-linkedin-pill\" href=\"https:\/\/www.linkedin.com\/in\/doctormohammedfatah\/\" rel=\"noopener noreferrer\" target=\"_blank\">\n<svg aria-hidden=\"true\" class=\"ols-linkedin-icon\" fill=\"currentColor\" viewbox=\"0 0 24 24\">\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<article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">1<\/div>\n<h2>Three Routes to an Alkene<\/h2>\n<\/div>\n<p>Cambridge asks you to <strong>recall the reactions, including reagents and conditions<\/strong>, by which alkenes can be produced. There are three routes on the syllabus, and each one is an example of a reaction type you meet elsewhere in AS organic chemistry.<\/p>\n<div class=\"ols-table-wrap\">\n<table class=\"ols-table\">\n<thead>\n<tr><th>Route<\/th><th>Starting material<\/th><th>Reagent and conditions<\/th><th>Type of reaction<\/th><\/tr>\n<\/thead>\n<tbody>\n<tr><td><strong>Elimination<\/strong><\/td><td>halogenoalkane<\/td><td>ethanolic NaOH, heat<\/td><td>elimination of HX<\/td><\/tr>\n<tr><td><strong>Dehydration<\/strong><\/td><td>alcohol<\/td><td>heated Al<sub>2<\/sub>O<sub>3<\/sub> catalyst, or concentrated H<sub>2<\/sub>SO<sub>4<\/sub> and heat<\/td><td>elimination of H<sub>2<\/sub>O<\/td><\/tr>\n<tr><td><strong>Cracking<\/strong><\/td><td>longer-chain alkane<\/td><td>heat with Al<sub>2<\/sub>O<sub>3<\/sub> catalyst<\/td><td>C\u2013C bond breaking to give a shorter alkane and an alkene<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div class=\"ols-key-box\">\n<p><strong>Key idea:<\/strong> All three routes create a C=C bond. Elimination and dehydration remove a small molecule (HX or H<sub>2<\/sub>O) from adjacent carbon atoms; cracking splits a long chain and leaves a double bond in one of the fragments.<\/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: Route and Small Molecule<\/h2>\n<p>Five quick questions on starting materials that are not used on this page.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-365\" class=\"h5p-iframe\" data-content-id=\"365\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Producing Alkenes Quick-Fire: Which Route and What Is Removed\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">2<\/div>\n<h2>Elimination of HX from a Halogenoalkane<\/h2>\n<\/div>\n<p>A halogenoalkane loses a <strong>hydrogen halide, HX<\/strong>, when it is heated with <strong>sodium hydroxide dissolved in ethanol<\/strong>. The hydroxide ion acts as a <strong>base<\/strong>: it removes a hydrogen atom from the carbon next to the C\u2013X carbon, the halide ion leaves, and a double bond forms between the two carbon atoms.<\/p>\n<p>For example, 2-bromopropane gives propene:<\/p>\n<p><strong>CH<sub>3<\/sub>CHBrCH<sub>3<\/sub> + NaOH \u2192 CH<sub>3<\/sub>CH=CH<sub>2<\/sub> + NaBr + H<sub>2<\/sub>O<\/strong><\/p>\n<p>The solvent matters. With <strong>ethanolic<\/strong> sodium hydroxide, elimination gives the alkene. With <strong>aqueous<\/strong> sodium hydroxide, the hydroxide ion acts as a nucleophile instead and substitution gives an alcohol. Exam questions often test this contrast.<\/p>\n<div class=\"ols-table-wrap\">\n<table class=\"ols-table\">\n<thead>\n<tr><th>Condition<\/th><th>Role of OH<sup>\u2212<\/sup><\/th><th>Reaction<\/th><th>Product<\/th><\/tr>\n<\/thead>\n<tbody>\n<tr><td><strong>NaOH in ethanol, heat<\/strong><\/td><td>base<\/td><td>elimination<\/td><td>alkene<\/td><\/tr>\n<tr><td><strong>NaOH in water, heat<\/strong><\/td><td>nucleophile<\/td><td>nucleophilic substitution<\/td><td>alcohol<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div class=\"ols-key-box\">\n<p><strong>Exam focus:<\/strong> Write &#8220;ethanolic sodium hydroxide&#8221; or &#8220;NaOH dissolved in ethanol&#8221; and &#8220;heat&#8221;. Writing &#8220;NaOH(aq)&#8221; loses the mark because it describes the substitution reaction.<\/p>\n<\/div>\n<div class=\"ols-figure-card\">\n<div class=\"ols-figure-image\"><img decoding=\"async\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/fix-60.jpg\" alt=\"2-bromopropane heated with ethanolic sodium hydroxide gives propene, sodium bromide and water\"><\/div>\n<div class=\"ols-figure-caption\"><p>Elimination removes H and X from adjacent carbon atoms, leaving a C=C double bond.<\/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 Solvent Does What<\/h2>\n<p>Drag the words and numbers into place to compare the two experiments.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-364\" class=\"h5p-iframe\" data-content-id=\"364\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Producing Alkenes Drag: Ethanolic and Aqueous Sodium Hydroxide Compared\"><\/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: Explain What Went Wrong<\/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-838\" class=\"h5p-iframe\" data-content-id=\"838\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Producing Alkenes Explain: The Wrong Solvent\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card purple\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">3<\/div>\n<h2>Dehydration of an Alcohol<\/h2>\n<\/div>\n<p>An alcohol loses a molecule of <strong>water<\/strong> to form an alkene in a <strong>dehydration<\/strong> reaction, which is another example of elimination. Cambridge gives two sets of conditions.<\/p>\n<h3>Route 1: heated catalyst<\/h3>\n<p>Alcohol vapour is passed over <strong>heated aluminium oxide, Al<sub>2<\/sub>O<sub>3<\/sub><\/strong>. The catalyst removes the OH group and a hydrogen atom from the neighbouring carbon.<\/p>\n<h3>Route 2: concentrated acid<\/h3>\n<p>The alcohol is heated with <strong>concentrated sulfuric acid<\/strong> (concentrated phosphoric acid is also used). The acid protonates the OH group so that water can leave, and the alkene forms.<\/p>\n<p>For example, ethanol gives ethene and water:<\/p>\n<p><strong>CH<sub>3<\/sub>CH<sub>2<\/sub>OH \u2192 CH<sub>2<\/sub>=CH<sub>2<\/sub> + H<sub>2<\/sub>O<\/strong><\/p>\n<p>With longer alcohols, the hydrogen atom can be removed from either side of the carbon carrying the OH group, so a <strong>mixture of alkenes<\/strong> can form. Butan-2-ol, for example, gives but-1-ene together with cis- and trans-but-2-ene.<\/p>\n<div class=\"ols-key-box\">\n<p><strong>Key idea:<\/strong> Dehydration is elimination of water. State the catalyst or acid and the need for heat, and remember that unsymmetrical alcohols can give more than one alkene, including geometrical isomers.<\/p>\n<\/div>\n<div class=\"ols-figure-card\">\n<div class=\"ols-figure-image\">\n<button class=\"ols-image-fullscreen-button ols-lightbox-trigger\" type=\"button\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/ethanol-dehydration-apparatus-diagram.jpg\" data-fullscreen-alt=\"Dehydration of ethanol to ethene over heated aluminium oxide, with the apparatus used to collect the ethene\" aria-label=\"Open image fullscreen\"><img decoding=\"async\" alt=\"Dehydration of ethanol to ethene over heated aluminium oxide, with the apparatus used to collect the ethene\" class=\"ols-hover-zoom-img ols-lightbox-target\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/ethanol-dehydration-apparatus-diagram.jpg\"\/><\/button>\n<\/div>\n<div class=\"ols-figure-caption\"><p>Dehydration removes H and OH from adjacent carbon atoms to form the alkene.<\/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: How Many Alkenes?<\/h2>\n<p>Find the carbon atoms next to the one carrying the OH group before you choose.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-366\" class=\"h5p-iframe\" data-content-id=\"366\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Producing Alkenes MCQ: Two Alkenes from Hexan-2-ol\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">4<\/div>\n<h2>Cracking of a Longer-Chain Alkane<\/h2>\n<\/div>\n<p><strong>Cracking<\/strong> breaks a long-chain alkane from crude oil into a shorter alkane and an alkene. The C\u2013C bonds are broken by heating the alkane over an <strong>aluminium oxide catalyst<\/strong>.<\/p>\n<p>For example, decane can be cracked into octane and ethene:<\/p>\n<p><strong>C<sub>10<\/sub>H<sub>22<\/sub> \u2192 C<sub>8<\/sub>H<sub>18<\/sub> + C<sub>2<\/sub>H<sub>4<\/sub><\/strong><\/p>\n<p>Cracking matters industrially because the demand for short-chain alkanes as fuels and for alkenes as chemical feedstock is greater than the supply from fractional distillation alone. The same reaction is listed in 14.1 as a source of more useful alkanes.<\/p>\n<div class=\"ols-key-box\">\n<p><strong>Exam focus:<\/strong> Any balanced cracking equation must have one alkane and at least one alkene on the right, and the total number of carbon and hydrogen atoms must match the starting alkane.<\/p>\n<\/div>\n<div class=\"ols-figure-card\">\n<div class=\"ols-figure-image\">\n<button class=\"ols-image-fullscreen-button ols-lightbox-trigger\" type=\"button\" data-fullscreen-src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/wave-26.jpg\" data-fullscreen-alt=\"Cracking of decane to octane and ethene with heat and a zeolite catalyst\" aria-label=\"Open image fullscreen\"><img decoding=\"async\" alt=\"Decane cracked to octane and ethene over an aluminium oxide catalyst, not a zeolite.\" class=\"ols-hover-zoom-img ols-lightbox-target\" src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/wave-26.jpg\"\/><\/button>\n<\/div>\n<div class=\"ols-figure-caption\"><p>Cracking a long-chain alkane always produces at least one alkene.<\/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: Balance the Cracking Equations<\/h2>\n<p>Type the missing formula or number into each equation.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-367\" class=\"h5p-iframe\" data-content-id=\"367\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Producing Alkenes Fill In: Completing Cracking Equations\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">5<\/div>\n<h2>Choosing a Route in Synthesis<\/h2>\n<\/div>\n<p>Synthesis questions in Topic 21 ask you to work backwards from a target molecule. If the target is an alkene, look at what you are given.<\/p>\n<div class=\"ols-table-wrap\">\n<table class=\"ols-table\">\n<thead>\n<tr><th>If you start with<\/th><th>Use<\/th><th>Then the alkene can be converted into<\/th><\/tr>\n<\/thead>\n<tbody>\n<tr><td><strong>a halogenoalkane<\/strong><\/td><td>ethanolic NaOH, heat<\/td><td>a diol (cold dilute acidified KMnO<sub>4<\/sub>) or an alcohol (steam and H<sub>3<\/sub>PO<sub>4<\/sub>)<\/td><\/tr>\n<tr><td><strong>an alcohol<\/strong><\/td><td>heated Al<sub>2<\/sub>O<sub>3<\/sub> or concentrated H<sub>2<\/sub>SO<sub>4<\/sub><\/td><td>a halogenoalkane (HX) or a dihalogenoalkane (X<sub>2<\/sub>)<\/td><\/tr>\n<tr><td><strong>a long-chain alkane<\/strong><\/td><td>cracking with Al<sub>2<\/sub>O<sub>3<\/sub><\/td><td>an addition polymer<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<div class=\"ols-key-box\">\n<p><strong>Remember:<\/strong> Each route to an alkene is the reverse of a reaction you also need: elimination reverses the addition of HX, and dehydration reverses the hydration of an alkene with steam.<\/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: Pick the Accurate Statement<\/h2>\n<p>In each round, choose the one statement that is accurate.<\/p>\n<div class=\"ols-h5p-frame\"><div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-839\" class=\"h5p-iframe\" data-content-id=\"839\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Producing Alkenes Summary: Choosing the Right Reagent\"><\/iframe><\/div><\/div>\n<\/section>\n<article class=\"ols-note-card\">\n<div class=\"ols-note-title\">\n<div class=\"ols-note-icon\">6<\/div>\n<h2>Common Exam Mistakes<\/h2>\n<\/div>\n<ul>\n<li>Do not write NaOH(aq) for elimination. Aqueous hydroxide gives substitution to an alcohol; <strong>ethanolic<\/strong> hydroxide gives the alkene.<\/li>\n<li>Do not describe dehydration as oxidation. No oxygen is gained and no hydrogen is lost from the carbon skeleton overall; a molecule of water is eliminated.<\/li>\n<li>Do not forget that dehydrating an unsymmetrical alcohol can give more than one alkene, and that but-2-ene exists as cis and trans isomers.<\/li>\n<li>Do not leave a cracking equation unbalanced. Count carbon and hydrogen atoms on both sides.<\/li>\n<\/ul>\n<\/article>\n\n<section class=\"ols-quicksnap-card\">\n<h2>QuickSnap<\/h2>\n<p>This text summary condenses the page into the essential exam ideas.<\/p>\n<ul class=\"ols-quicksnap-list\">\n<li><strong>Elimination:<\/strong> halogenoalkane + NaOH in ethanol, heat \u2192 alkene + NaX + H<sub>2<\/sub>O.<\/li>\n<li><strong>Dehydration:<\/strong> alcohol \u2192 alkene + H<sub>2<\/sub>O, using heated Al<sub>2<\/sub>O<sub>3<\/sub> or concentrated H<sub>2<\/sub>SO<sub>4<\/sub> and heat.<\/li>\n<li><strong>Cracking:<\/strong> long-chain alkane, heat with Al<sub>2<\/sub>O<sub>3<\/sub> \u2192 shorter alkane + alkene.<\/li>\n<li><strong>Solvent matters:<\/strong> ethanolic NaOH eliminates, aqueous NaOH substitutes.<\/li>\n<li><strong>Mixtures:<\/strong> unsymmetrical alcohols and halogenoalkanes can give more than one alkene.<\/li>\n<\/ul>\n<\/section>\n<section class=\"ols-faq-card\">\n<h2>FAQs<\/h2>\n<p>These questions address the points students most often confuse when producing alkenes.<\/p>\n<div class=\"ols-faq-item\"><h3>Why does the solvent change the product of the halogenoalkane reaction?<\/h3><p>In ethanol the hydroxide ion behaves as a base and removes a proton, so HX is eliminated and an alkene forms. In water it behaves as a nucleophile and replaces the halogen, so an alcohol forms.<\/p><\/div>\n<div class=\"ols-faq-item\"><h3>Which conditions does Cambridge accept for dehydration?<\/h3><p>Either passing the alcohol vapour over heated aluminium oxide, or heating the alcohol with concentrated sulfuric acid. Concentrated phosphoric acid is also acceptable as the acid catalyst.<\/p><\/div>\n<div class=\"ols-faq-item\"><h3>Can dehydration give more than one alkene?<\/h3><p>Yes. If the carbon atoms on either side of the C\u2013OH carbon both carry hydrogen atoms, elimination can occur in two directions, and the but-2-ene formed from butan-2-ol also exists as cis and trans isomers.<\/p><\/div>\n<div class=\"ols-faq-item\"><h3>Is cracking an elimination reaction?<\/h3><p>No. Cracking breaks a carbon\u2013carbon bond in a long chain to give two smaller molecules, one of which is an alkene. Elimination removes a small molecule from adjacent carbon atoms of one molecule.<\/p><\/div>\n<\/section>\n<section class=\"ols-related-card\">\n<h2>Related Alkene Revision Notes<\/h2>\n<p>Continue through CIE Topic 14 by linking the production of alkenes to their bonding, reactions and mechanisms.<\/p>\n<div class=\"ols-related-grid\">\n<a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-13-an-introduction-to-as-level-organic-chemistry\/shapes-of-organic-molecules\/alkene-bonding\/\">Alkene Bonding<\/a>\n<a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/electrophilic-addition-mechanism\/\">Electrophilic Addition Mechanism<\/a>\n<a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/\">Reactions of Alkenes<\/a>\n<a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-14-hydrocarbons\/alkenes\/reactions-of-alkenes\/steam\/\">Steam<\/a>\n<a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-15-halogen-compounds\/\">Topic 15 Halogen Compounds<\/a>\n<a class=\"ols-related-item\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/revision-notes\/a-level-chemistry\/cie\/topic-16-hydroxy-compounds\/\">Topic 16 Hydroxy Compounds<\/a>\n<\/div>\n<\/section>\n<script type=\"application\/ld+json\">{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@graph\": [\n    {\n      \"@type\": \"WebPage\",\n      \"@id\": 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<\/style>\r\n\r\n  <div class=\"ols-course-cta-card\">\r\n\r\n    <div class=\"ols-course-cta-top\">\r\n\r\n      <a class=\"ols-course-cta-image-link\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/product\/alkenes-topic-14-2-cambridge-international\/\" aria-label=\"Open the Cambridge International AS and A Level Chemistry Topic 14.2 Alkenes course page\">\r\n\r\n        <div class=\"ols-course-cta-image\">\r\n          <img decoding=\"async\"\r\n            src=\"https:\/\/www.onlinelearningsystem.net\/xyz\/wp-content\/uploads\/2026\/09\/cambridge-international-a-level-chemistry-topic-14-2-alkenes-interactive-course-banner-v2.jpg\"\r\n            alt=\"Cambridge International AS and A Level Chemistry Topic 14.2 Alkenes interactive course banner\"\r\n          >\r\n        <\/div>\r\n\r\n      <\/a>\r\n\r\n      <div class=\"ols-course-cta-content\">\r\n\r\n        <div class=\"ols-course-cta-header-row\">\r\n\r\n          <div class=\"ols-course-cta-kicker\">\r\n            Cambridge 9701 | Topic 14.2 Alkenes Course\r\n          <\/div>\r\n\r\n          <a class=\"ols-course-button ols-course-button-top\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/product\/alkenes-topic-14-2-cambridge-international\/\">\r\n            View Course\r\n          <\/a>\r\n\r\n        <\/div>\r\n\r\n        <h2>\r\n          Master Alkenes for Cambridge International AS &amp; A Level Chemistry\r\n        <\/h2>\r\n\r\n      <\/div>\r\n\r\n    <\/div>\r\n\r\n    <div class=\"ols-course-cta-intro-stats\">\r\n\r\n      <p class=\"ols-course-cta-intro\">\r\n        Continue from these free revision notes into the full Topic 14.2 Alkenes course. The guided video lessons are ready now; the Cambridge International MCQ bank, teacher-marked short-answer questions and KASP spec-point report are being written, and the course opens for enrolment as soon as they are complete.\r\n      <\/p>\r\n\r\n      <div class=\"ols-course-cta-stats\">\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>Recorded lessons<\/span>\n          <strong>Coming soon<\/strong>\r\n        <\/div>\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>Video lessons<\/span>\n          <strong>Coming soon<\/strong>\r\n        <\/div>\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>MCQ practice<\/span>\n          <strong>Coming soon<\/strong>\r\n        <\/div>\r\n\r\n        <div class=\"ols-course-stat\">\r\n          <span>SAQ practice<\/span>\n          <strong>Coming soon<\/strong>\r\n        <\/div>\r\n\r\n      <\/div>\r\n\r\n    <\/div>\r\n\r\n    <div class=\"ols-course-cta-features\">\r\n\r\n      <div class=\"ols-course-feature\">\r\n        <h3>Guided video teaching<\/h3>\r\n        <p>\r\n          Learn the chemistry and exam technique through structured video lessons with worked examples and walkthroughs.\r\n        <\/p>\r\n      <\/div>\r\n\r\n      <div class=\"ols-course-feature\">\r\n        <h3>Instant MCQ feedback<\/h3>\r\n        <p>\r\n          Auto-marked MCQ quizzes provide immediate diagnostic feedback for every answer choice.\r\n        <\/p>\r\n      <\/div>\r\n\r\n      <div class=\"ols-course-feature\">\r\n        <h3>Teacher-marked SAQs<\/h3>\r\n        <p>\r\n          Submit written exam responses and receive chemistry specialist feedback with improvement guidance.\r\n        <\/p>\r\n      <\/div>\r\n\r\n      <div class=\"ols-course-feature\">\r\n        <h3>Progress tracking<\/h3>\r\n        <p>\r\n          Identify strengths and weaknesses across the full Topic 14.2 specification with targeted reporting.\r\n        <\/p>\r\n      <\/div>\r\n\r\n    <\/div>\r\n\r\n    <div class=\"ols-course-animation-wrap\">\r\n\r\n      <h3 class=\"ols-course-animation-title\">\r\n        See how the course works\r\n      <\/h3>\r\n\r\n      <div class=\"ols-animation-frame-shell\">\r\n        <iframe\r\n          id=\"olsCourseAnimationFrame001\"\r\n          title=\"OLS course preview animation\"\r\n          loading=\"lazy\"\r\n          referrerpolicy=\"no-referrer\">\r\n        <\/iframe>\r\n\r\n        <button\r\n          class=\"ols-animation-start-overlay\"\r\n          id=\"olsCourseAnimationStart001\"\r\n          type=\"button\"\r\n          aria-label=\"Play OLS course preview animation\">\r\n          <span class=\"ols-animation-start-content\">\r\n            <span class=\"ols-animation-play-circle\" aria-hidden=\"true\">\r\n              <span class=\"ols-animation-play-icon\"><\/span>\r\n            <\/span>\r\n            <span class=\"ols-animation-start-text\">\r\n              Play course preview animation\r\n            <\/span>\r\n          <\/span>\r\n        <\/button>\r\n\r\n        <button\r\n          class=\"ols-animation-pause-button\"\r\n          id=\"olsCourseAnimationPause001\"\r\n          type=\"button\"\r\n          aria-label=\"Pause course preview animation\">\r\n          Pause\r\n        <\/button>\r\n      <\/div>\r\n\r\n      <p class=\"ols-course-video-status\">\r\n        Click play to start the course preview animation.\r\n      <\/p>\r\n\r\n    <\/div>\r\n\r\n    <div class=\"ols-course-cta-bottom\">\r\n\r\n      <a class=\"ols-course-button\" href=\"https:\/\/www.onlinelearningsystem.net\/xyz\/product\/alkenes-topic-14-2-cambridge-international\/\">\r\n        View Alkenes Topic 14.2 Course\r\n      <\/a>\r\n\r\n    <\/div>\r\n\r\n  <\/div>\r\n\r\n  <template id=\"olsCourseAnimationTemplate001\">\r\n<!DOCTYPE html>\r\n<html lang=\"en\">\r\n<head>\r\n<meta charset=\"UTF-8\">\r\n<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\">\r\n<title>OLS Combined Promo Animation<\/title>\r\n\r\n<style>\r\n*{box-sizing:border-box;}\r\n\r\nhtml.ols-animation-paused *,\r\nhtml.ols-animation-paused *::before,\r\nhtml.ols-animation-paused *::after{\r\n  animation-play-state:paused!important;\r\n}\r\n\r\n:root{\r\n  --ols-video-screen-w:1180;\r\n  --ols-video-screen-h:664;\r\n  --ols-video-screen-scale:1;\r\n  --ols-mcq-screen-w:1360;\r\n  --ols-mcq-screen-h:1130;\r\n  --ols-mcq-screen-scale:1;\r\n  --ols-saq-screen-w:1360;\r\n  --ols-saq-screen-h:965;\r\n  --ols-saq-screen-scale:1;\r\n}\r\n\r\nhtml,\r\nbody{\r\n  width:100%;\r\n  height:100%;\r\n}\r\n\r\nbody{\r\n  margin:0;\r\n  overflow:hidden;\r\n  font-family:Poppins,Arial,sans-serif;\r\n  background:#e9efff;\r\n}\r\n\r\n.ols-combined-stage{\r\n  position:relative;\r\n  width:100vw;\r\n  height:100vh;\r\n  overflow:hidden;\r\n  background:\r\n    radial-gradient(circle at top left,rgba(70,127,247,0.14),transparent 34%),\r\n    linear-gradient(135deg,#f8fbff 0%,#e9efff 100%);\r\n}\r\n\r\n.ols-scene{\r\n  position:absolute;\r\n  inset:0;\r\n  width:100vw;\r\n  height:100vh;\r\n  opacity:0;\r\n  visibility:hidden;\r\n  pointer-events:none;\r\n}\r\n\r\n.ols-scene.active{\r\n  opacity:1;\r\n  visibility:visible;\r\n  pointer-events:auto;\r\n}\r\n\r\n.ols-scene.fade-out{\r\n  animation:olsSceneFadeOut 0.85s ease forwards;\r\n}\r\n\r\n@keyframes olsSceneFadeOut{\r\n  to{\r\n    opacity:0;\r\n    visibility:hidden;\r\n  }\r\n}\r\n\r\n.ols-title-cursor{\r\n  display:inline-block;\r\n  width:5px;\r\n  height:0.85em;\r\n  background:#1C244B;\r\n  margin-left:8px;\r\n  transform:translateY(8px);\r\n  animation:olsBlink 0.8s infinite;\r\n}\r\n\r\n.cursor{\r\n  display:inline-block;\r\n  width:3px;\r\n  height:28px;\r\n  background:#1c244b;\r\n  margin-left:3px;\r\n  transform:translateY(5px);\r\n  animation:olsBlink 0.8s infinite;\r\n}\r\n\r\n@keyframes olsBlink{\r\n  0%,45%{opacity:1;}\r\n  46%,100%{opacity:0;}\r\n}\r\n\r\n.ols-video-stage,\r\n.ols-mcq-stage,\r\n.ols-saq-stage{\r\n  width:100vw;\r\n  height:100vh;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:center;\r\n  padding:0;\r\n  overflow:hidden;\r\n  background:\r\n    radial-gradient(circle at top left,rgba(70,127,247,0.14),transparent 34%),\r\n    linear-gradient(135deg,#f8fbff 0%,#e9efff 100%);\r\n}\r\n\r\n.ols-video-title-screen,\r\n.ols-mcq-intro-screen,\r\n.ols-saq-intro{\r\n  position:absolute;\r\n  inset:0;\r\n  z-index:50;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:center;\r\n  background:\r\n    radial-gradient(circle at top left,rgba(70,127,247,0.14),transparent 34%),\r\n    linear-gradient(135deg,#f8fbff 0%,#e9efff 100%);\r\n  opacity:1;\r\n  visibility:visible;\r\n  pointer-events:none;\r\n}\r\n\r\n.ols-video-title-screen.hide{animation:olsVideoTitleFadeOut 0.85s ease forwards;}\r\n.ols-mcq-intro-screen.hide{animation:olsMcqIntroFadeOut 0.85s ease forwards;}\r\n.ols-saq-intro.hide{animation:olsSaqIntroFadeOut 0.85s ease forwards;}\r\n\r\n@keyframes olsVideoTitleFadeOut{to{opacity:0;visibility:hidden;}}\r\n@keyframes olsMcqIntroFadeOut{to{opacity:0;visibility:hidden;}}\r\n@keyframes olsSaqIntroFadeOut{to{opacity:0;visibility:hidden;}}\r\n\r\n.ols-video-title-wrap,\r\n.ols-mcq-intro-title-wrap,\r\n.ols-saq-intro-title-wrap{\r\n  max-width:1250px;\r\n  padding:0 34px;\r\n  text-align:center;\r\n}\r\n\r\n.ols-video-title,\r\n.ols-mcq-intro-title,\r\n.ols-saq-intro-title{\r\n  margin:0;\r\n  font-family:Poppins,Arial,sans-serif;\r\n  font-size:clamp(52px,8vw,124px);\r\n  font-weight:600;\r\n  line-height:1.08;\r\n  color:#1C244B;\r\n  text-shadow:-9px 0 9px rgba(28,36,75,0.16);\r\n  letter-spacing:-0.045em;\r\n}\r\n\r\n#videoTitleText,\r\n#mcqIntroTitleText,\r\n#saqIntroTitleText{\r\n  white-space:pre-wrap;\r\n}\r\n\r\n.ols-video-scene{\r\n  width:100%;\r\n  height:100%;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:center;\r\n  opacity:0;\r\n  visibility:hidden;\r\n}\r\n\r\n.ols-video-scene.show{\r\n  visibility:visible;\r\n  animation:olsVideoSceneIn 1s ease forwards;\r\n}\r\n\r\n@keyframes olsVideoSceneIn{to{opacity:1;}}\r\n\r\n.ols-video-scale-wrap{\r\n  width:calc(var(--ols-video-screen-w) * 1px);\r\n  height:calc(var(--ols-video-screen-h) * 1px);\r\n  transform:scale(var(--ols-video-screen-scale));\r\n  transform-origin:center center;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:center;\r\n}\r\n\r\n.ols-video-card{\r\n  width:1180px;\r\n  height:664px;\r\n  border-radius:28px;\r\n  overflow:hidden;\r\n  background:#1C244B;\r\n  box-shadow:0 28px 80px rgba(28,36,75,0.28);\r\n  transform:translateY(24px) scale(0.96);\r\n  opacity:0;\r\n}\r\n\r\n.ols-video-scene.show .ols-video-card{\r\n  animation:olsVideoCardIn 1s cubic-bezier(.18,.89,.32,1.12) forwards;\r\n  animation-delay:0.2s;\r\n}\r\n\r\n@keyframes olsVideoCardIn{\r\n  to{\r\n    transform:translateY(0) scale(1);\r\n    opacity:1;\r\n  }\r\n}\r\n\r\n.ols-video-card video{\r\n  display:block;\r\n  width:100%;\r\n  height:100%;\r\n  aspect-ratio:16 \/ 9;\r\n  object-fit:cover;\r\n  border:0;\r\n}\r\n\r\n.ols-mcq-scale-wrap,\r\n.ols-saq-scale-wrap{\r\n  width:calc(var(--ols-mcq-screen-w) * 1px);\r\n  height:calc(var(--ols-mcq-screen-h) * 1px);\r\n  transform:scale(var(--ols-mcq-screen-scale));\r\n  transform-origin:center center;\r\n  display:flex;\r\n  justify-content:center;\r\n  align-items:flex-start;\r\n}\r\n\r\n.ols-saq-scale-wrap{\r\n  width:calc(var(--ols-saq-screen-w) * 1px);\r\n  height:calc(var(--ols-saq-screen-h) * 1px);\r\n  transform:scale(var(--ols-saq-screen-scale));\r\n}\r\n\r\n.ols-mcq-screen{\r\n  width:1360px;\r\n  height:1130px;\r\n  border-radius:22px;\r\n  overflow:hidden;\r\n  background:#eaf0ff;\r\n  box-shadow:0 26px 70px rgba(28,36,75,0.22);\r\n  opacity:0;\r\n  transform:translateY(24px) scale(0.96);\r\n}\r\n\r\n.ols-mcq-screen.show{\r\n  animation:olsMcqScreenEnter 1s ease forwards;\r\n}\r\n\r\n@keyframes olsMcqScreenEnter{\r\n  from{opacity:0;transform:translateY(24px) scale(0.96);}\r\n  to{opacity:1;transform:translateY(0) scale(1);}\r\n}\r\n\r\n.mcq-question-area{\r\n  background:#eaf0ff;\r\n  padding:28px 30px 30px;\r\n  position:relative;\r\n  height:610px;\r\n}\r\n\r\n.mcq-question-lead{\r\n  margin:0 0 14px;\r\n  font-size:24px;\r\n  line-height:1.35;\r\n  color:#111827;\r\n}\r\n\r\n.mcq-ionic-table{\r\n  border-collapse:collapse;\r\n  width:500px;\r\n  margin-bottom:8px;\r\n  font-size:21px;\r\n  color:#111827;\r\n}\r\n\r\n.mcq-ionic-table th,\r\n.mcq-ionic-table td{\r\n  border:1.5px solid #c9ced8;\r\n  padding:12px 18px;\r\n  text-align:center;\r\n}\r\n\r\n.mcq-ionic-table th{\r\n  background:#f2f2f2;\r\n  font-weight:700;\r\n}\r\n\r\n.mcq-ionic-table td{\r\n  background:#eaf0ff;\r\n}\r\n\r\n.mcq-question-main{\r\n  margin:6px 0 28px;\r\n  font-size:24px;\r\n  line-height:1.35;\r\n  color:#111827;\r\n}\r\n\r\n.mcq-options-wrap{\r\n  display:flex;\r\n  flex-direction:column;\r\n  gap:17px;\r\n  max-width:1200px;\r\n}\r\n\r\n.mcq-option-row{\r\n  display:flex;\r\n  align-items:center;\r\n  min-height:34px;\r\n  position:relative;\r\n}\r\n\r\n.mcq-radio{\r\n  width:28px;\r\n  height:28px;\r\n  border-radius:50%;\r\n  border:2px solid #6b7280;\r\n  margin-right:16px;\r\n  background:transparent;\r\n  position:relative;\r\n  flex:0 0 auto;\r\n}\r\n\r\n.mcq-radio::after{\r\n  content:\"\";\r\n  position:absolute;\r\n  inset:5px;\r\n  border-radius:50%;\r\n  background:#6b7280;\r\n  opacity:0;\r\n  transform:scale(0.4);\r\n  transition:opacity 0.25s ease,transform 0.25s ease;\r\n}\r\n\r\n.mcq-option-row.selected .mcq-radio::after{\r\n  opacity:1;\r\n  transform:scale(1);\r\n}\r\n\r\n.mcq-radio-ripple{\r\n  position:absolute;\r\n  left:14px;\r\n  top:50%;\r\n  width:28px;\r\n  height:28px;\r\n  border-radius:50%;\r\n  border:2px solid rgba(28,36,75,0.28);\r\n  transform:translate(-50%,-50%) scale(1);\r\n  opacity:0;\r\n  pointer-events:none;\r\n}\r\n\r\n.mcq-option-row.clicking .mcq-radio-ripple{\r\n  animation:mcqRipple 0.75s ease forwards;\r\n}\r\n\r\n@keyframes mcqRipple{\r\n  0%{opacity:0.65;transform:translate(-50%,-50%) scale(1);}\r\n  100%{opacity:0;transform:translate(-50%,-50%) scale(2.5);}\r\n}\r\n\r\n.mcq-option-label{\r\n  font-size:23px;\r\n  color:#111827;\r\n}\r\n\r\n.mcq-specific-feedback{\r\n  display:inline-flex;\r\n  align-items:center;\r\n  margin-left:18px;\r\n  min-height:38px;\r\n  opacity:0;\r\n  transform:translateX(-8px);\r\n}\r\n\r\n.mcq-specific-feedback.show{\r\n  opacity:1;\r\n  transform:translateX(0);\r\n  transition:opacity 0.35s ease,transform 0.35s ease;\r\n}\r\n\r\n.mcq-cross-icon{\r\n  width:26px;\r\n  height:26px;\r\n  border-radius:50%;\r\n  border:2px solid #d83255;\r\n  color:#d83255;\r\n  display:inline-flex;\r\n  justify-content:center;\r\n  align-items:center;\r\n  font-size:18px;\r\n  font-weight:700;\r\n  margin-right:12px;\r\n  opacity:0;\r\n  transform:scale(0.4);\r\n}\r\n\r\n.mcq-cross-icon.show{\r\n  animation:mcqCrossPop 0.35s ease forwards;\r\n}\r\n\r\n@keyframes mcqCrossPop{\r\n  70%{opacity:1;transform:scale(1.18);}\r\n  100%{opacity:1;transform:scale(1);}\r\n}\r\n\r\n.mcq-specific-feedback-text{\r\n  display:inline-block;\r\n  background:#fff4b8;\r\n  color:#111827;\r\n  padding:8px 16px;\r\n  font-size:22px;\r\n  line-height:1.35;\r\n  min-width:850px;\r\n  min-height:44px;\r\n}\r\n\r\n.mcq-submit-button{\r\n  position:absolute;\r\n  right:34px;\r\n  bottom:30px;\r\n  border:0;\r\n  border-radius:999px;\r\n  background:#1C244B;\r\n  color:#ffffff;\r\n  padding:14px 28px;\r\n  font-size:18px;\r\n  font-weight:600;\r\n  box-shadow:0 14px 32px rgba(28,36,75,0.25);\r\n  cursor:default;\r\n  transition:transform 0.2s ease,box-shadow 0.2s ease,background 0.2s ease;\r\n}\r\n\r\n.mcq-submit-button.clicked{\r\n  transform:translateY(2px) scale(0.97);\r\n  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class=\"ols-mcq-scale-wrap\">\r\n        <main id=\"mcqScreen\" class=\"ols-mcq-screen\">\r\n          <section class=\"mcq-question-area\">\r\n            <p class=\"mcq-question-lead\">Some ionic radii are shown.<\/p>\r\n\r\n            <table class=\"mcq-ionic-table\">\r\n              <thead>\r\n                <tr>\r\n                  <th>Ion<\/th>\r\n                  <th>Ionic radius \/ nm<\/th>\r\n                <\/tr>\r\n              <\/thead>\r\n              <tbody>\r\n                <tr><td>Na<sup>+<\/sup><\/td><td>0.102<\/td><\/tr>\r\n                <tr><td>K<sup>+<\/sup><\/td><td>0.138<\/td><\/tr>\r\n                <tr><td>F<sup>\u2212<\/sup><\/td><td>0.133<\/td><\/tr>\r\n                <tr><td>Cl<sup>\u2212<\/sup><\/td><td>0.180<\/td><\/tr>\r\n              <\/tbody>\r\n            <\/table>\r\n\r\n            <p class=\"mcq-question-main\">Which compound has the strongest ionic bonding?<\/p>\r\n\r\n            <div class=\"mcq-options-wrap\">\r\n              <div id=\"mcqWrongOption\" class=\"mcq-option-row\">\r\n                <span class=\"mcq-radio\"><\/span>\r\n                <span class=\"mcq-radio-ripple\"><\/span>\r\n                <span class=\"mcq-option-label\">sodium chloride<\/span>\r\n\r\n                <span id=\"mcqSpecificFeedback\" class=\"mcq-specific-feedback\">\r\n                  <span id=\"mcqCrossIcon\" class=\"mcq-cross-icon\">\u00d7<\/span>\r\n                  <span class=\"mcq-specific-feedback-text\">\r\n                    <span id=\"mcqSpecificText\"><\/span><span id=\"mcqSpecificCursor\" class=\"cursor mcq-specific-cursor\" style=\"display:none;\"><\/span>\r\n                  <\/span>\r\n                <\/span>\r\n              <\/div>\r\n\r\n              <div class=\"mcq-option-row\"><span class=\"mcq-radio\"><\/span><span class=\"mcq-radio-ripple\"><\/span><span class=\"mcq-option-label\">potassium chloride<\/span><\/div>\r\n              <div class=\"mcq-option-row\"><span class=\"mcq-radio\"><\/span><span class=\"mcq-radio-ripple\"><\/span><span class=\"mcq-option-label\">sodium fluoride<\/span><\/div>\r\n              <div class=\"mcq-option-row\"><span class=\"mcq-radio\"><\/span><span class=\"mcq-radio-ripple\"><\/span><span class=\"mcq-option-label\">potassium fluoride<\/span><\/div>\r\n            <\/div>\r\n\r\n            <button id=\"mcqSubmitButton\" class=\"mcq-submit-button\">Submit answer<\/button>\r\n          <\/section>\r\n\r\n          <section id=\"mcqGeneralFeedback\" class=\"mcq-general-feedback\">\r\n            <span id=\"mcqGeneralText\"><\/span><span id=\"mcqGeneralCursor\" class=\"cursor mcq-general-cursor\" style=\"display:none;\"><\/span>\r\n          <\/section>\r\n        <\/main>\r\n      <\/div>\r\n    <\/div>\r\n  <\/section>\r\n\r\n  <section id=\"sceneSaq\" class=\"ols-scene\">\r\n    <div class=\"ols-saq-stage\">\r\n      <div id=\"saqIntro\" class=\"ols-saq-intro\">\r\n        <div 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