{"id":267285,"date":"2025-07-23T11:56:01","date_gmt":"2025-07-23T11:56:01","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=267285"},"modified":"2025-07-23T11:56:03","modified_gmt":"2025-07-23T11:56:03","slug":"compound-a-c7h11br-is-treated-with-magnesium-in-ether-to-give-b-c7h11mgbr-which-reacts-violently-with-d2o-togive-1-methylcyclohexene-with-a-deuterium-atom-on-the-methyl-group-c","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/07\/23\/compound-a-c7h11br-is-treated-with-magnesium-in-ether-to-give-b-c7h11mgbr-which-reacts-violently-with-d2o-togive-1-methylcyclohexene-with-a-deuterium-atom-on-the-methyl-group-c\/","title":{"rendered":"Compound A (C7H11Br) is treated with magnesium in ether to give B (C7H11MgBr), which reacts violently with D2O togive 1-methylcyclohexene with a deuterium atom on the methyl group (C)."},"content":{"rendered":"\n<p>Compound A (C7H11Br) is treated with magnesium in ether to give B (C7H11MgBr), which reacts violently with D2O togive 1-methylcyclohexene with a deuterium atom on the methyl group (C). Reaction of B with acetone (CH3COCH3)followed by hydrolysis gives D (C10H18O). Heating D with concentrated H2SO4 gives E (C10H16), which decolorizestwo equivalents of Br2 to give F (C10H16Br4). E undergoes hydrogenation with excess H2 and a Pt catalyst to giveisobutylcyclohexane. Determine the structures of compounds A through F, and show your reasoning throughout<\/p>\n\n\n\n<p><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-1-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p>To solve this problem, let&#8217;s break down each step of the reaction and determine the structure of each compound based on the provided information.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Compound A (C7H11Br):<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Structure<\/strong>: Compound A is likely a bromoalkane. Given that it&#8217;s treated with magnesium to form a Grignard reagent, it suggests that A is a <strong>bromocyclohexane derivative<\/strong>.<\/li>\n\n\n\n<li><strong>Reasoning<\/strong>: The presence of a bromine atom indicates that A is likely <strong>1-bromocyclohexane<\/strong> (C7H11Br), where the bromine is attached to the cyclohexane ring.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Compound B (C7H11MgBr):<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Structure<\/strong>: Compound B is the Grignard reagent, formed by reacting compound A with magnesium in ether. This results in the formation of a <strong>cyclohexylmagnesium bromide<\/strong> (C7H11MgBr).<\/li>\n\n\n\n<li><strong>Reasoning<\/strong>: The magnesium inserts between the carbon-bromine bond, forming the Grignard reagent, where the bromine is replaced by a <strong>magnesium-bromine bond<\/strong>.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Reaction with D2O:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>When compound B reacts with D2O (heavy water), the result is <strong>1-methylcyclohexene<\/strong> with a deuterium atom on the methyl group (C).<\/li>\n\n\n\n<li><strong>Structure of C<\/strong>: The reaction forms <strong>1-methylcyclohexene<\/strong> (C7H12) with a deuterium atom replacing the hydrogen on the methyl group. This suggests the formation of a <strong>deuterated 1-methylcyclohexene<\/strong>.<\/li>\n\n\n\n<li><strong>Reasoning<\/strong>: The Grignard reagent acts as a strong base and abstracts a proton from D2O, replacing it with a deuterium atom (D).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Compound D (C10H18O):<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Structure<\/strong>: Reaction of B with acetone (CH3COCH3) forms an <strong>addition product<\/strong>. The Grignard reagent adds to the carbonyl group of acetone, resulting in a <strong>tert-butyl alcohol<\/strong> structure after hydrolysis.<\/li>\n\n\n\n<li><strong>Reasoning<\/strong>: The product is <strong>D<\/strong>, a tertiary alcohol with the formula C10H18O, which matches the structure of <strong>2-methyl-2-pentanol<\/strong> (a product of the Grignard reaction with acetone).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Compound E (C10H16):<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Structure<\/strong>: Heating compound D with concentrated H2SO4 leads to <strong>dehydration<\/strong>, resulting in the formation of <strong>E<\/strong>, a cyclohexene derivative (C10H16).<\/li>\n\n\n\n<li><strong>Reasoning<\/strong>: The dehydration removes water from the alcohol, forming a <strong>double bond<\/strong> to create a cyclohexene structure, specifically <strong>1-methylcyclohexene<\/strong>.<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Compound F (C10H16Br4):<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Structure<\/strong>: Decolorization of bromine in the presence of compound E indicates the presence of a <strong>reactive alkene<\/strong>. The alkene reacts with two equivalents of Br2, leading to the formation of a <strong>tetra-bromo<\/strong> derivative.<\/li>\n\n\n\n<li><strong>Reasoning<\/strong>: The <strong>dibromination<\/strong> occurs across the double bond of <strong>1-methylcyclohexene<\/strong>, resulting in <strong>F<\/strong>, which is <strong>1,2,3,4-tetrabromocyclohexane<\/strong> (C10H16Br4).<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Final Structure of Compounds A\u2013F:<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>A (C7H11Br)<\/strong>: 1-bromocyclohexane.<\/li>\n\n\n\n<li><strong>B (C7H11MgBr)<\/strong>: Cyclohexylmagnesium bromide.<\/li>\n\n\n\n<li><strong>C (C7H12D)<\/strong>: 1-deuterated methylcyclohexene.<\/li>\n\n\n\n<li><strong>D (C10H18O)<\/strong>: 2-methyl-2-pentanol (tert-butyl alcohol).<\/li>\n\n\n\n<li><strong>E (C10H16)<\/strong>: 1-methylcyclohexene.<\/li>\n\n\n\n<li><strong>F (C10H16Br4)<\/strong>: 1,2,3,4-tetrabromocyclohexane.<\/li>\n<\/ol>\n\n\n\n<p>This sequence describes the formation and transformations of each compound, leading to their final structures.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/07\/learnexams-banner6-1683.jpeg\" alt=\"\" class=\"wp-image-267293\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Compound A (C7H11Br) is treated with magnesium in ether to give B (C7H11MgBr), which reacts violently with D2O togive 1-methylcyclohexene with a deuterium atom on the methyl group (C). Reaction of B with acetone (CH3COCH3)followed by hydrolysis gives D (C10H18O). Heating D with concentrated H2SO4 gives E (C10H16), which decolorizestwo equivalents of Br2 to give [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-267285","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/267285","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=267285"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/267285\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=267285"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=267285"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=267285"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}