{"id":237627,"date":"2025-06-17T11:29:22","date_gmt":"2025-06-17T11:29:22","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=237627"},"modified":"2025-06-17T11:29:24","modified_gmt":"2025-06-17T11:29:24","slug":"what-is-true-about-the-ir-spectrum-of-23-dimethyl-2-butene","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/17\/what-is-true-about-the-ir-spectrum-of-23-dimethyl-2-butene\/","title":{"rendered":"What is true about the IR spectrum of 2,3-dimethyl-2-butene"},"content":{"rendered":"\n

What is true about the IR spectrum of 2,3-dimethyl-2-butene? There will be no peak (C-=C) at 1600-1700 cm-1 There will be a peak (C-H; sp2-s bond) at 3100 cm 1 There will be a peak (C-H; sp3-s bond) above 3000 cm There will be a peak (C-H; sp2-s bond) just below 3000 cm-1 None of these<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Correct Answer:<\/strong>
There will be a peak (C\u2013H; sp\u00b2\u2013s bond) at 3100 cm\u207b\u00b9.<\/strong><\/p>\n\n\n\n

\n\n\n\n

Explanation:<\/h3>\n\n\n\n

The IR (infrared) spectrum of 2,3-dimethyl-2-butene<\/strong>, a symmetrical alkene with the molecular formula C\u2086H\u2081\u2082, shows several characteristic peaks based on the functional groups present in the molecule. The key structural feature in this compound is the carbon\u2013carbon double bond (C=C)<\/strong>, and alkyl groups<\/strong> attached to it.<\/p>\n\n\n\n

Let us analyze the given options based on infrared spectroscopy:<\/p>\n\n\n\n

    \n
  1. \u201cThere will be no peak (C=C) at 1600\u20131700 cm\u207b\u00b9\u201d:<\/strong>
    This is false<\/strong>. Alkenes generally exhibit a weak to medium intensity peak for the C=C stretch<\/strong> in the region of 1600\u20131680 cm\u207b\u00b9<\/strong>. Even though 2,3-dimethyl-2-butene is symmetrical (reducing the dipole moment change and intensity of the signal), the C=C stretch may still appear as a very weak peak<\/strong>, not completely absent.<\/li>\n\n\n\n
  2. \u201cThere will be a peak (C\u2013H; sp\u00b2\u2013s bond) at 3100 cm\u207b\u00b9\u201d:<\/strong>
    This is true<\/strong>. Alkenes have vinylic hydrogen atoms<\/strong> (hydrogens attached to sp\u00b2-hybridized carbon atoms), which produce C\u2013H stretching<\/strong> vibrations just above 3000 cm\u207b\u00b9<\/strong>, typically around 3020\u20133100 cm\u207b\u00b9<\/strong>. So, the IR spectrum of 2,3-dimethyl-2-butene will show a peak in this range.<\/li>\n\n\n\n
  3. \u201cThere will be a peak (C\u2013H; sp\u00b3\u2013s bond) above 3000 cm\u207b\u00b9\u201d:<\/strong>
    This is false<\/strong>. The C\u2013H stretch from sp\u00b3-hybridized carbon atoms<\/strong> typically appears at 2850\u20132960 cm\u207b\u00b9<\/strong>, which is below 3000 cm\u207b\u00b9<\/strong>, not above.<\/li>\n\n\n\n
  4. \u201cThere will be a peak (C\u2013H; sp\u00b2\u2013s bond) just below 3000 cm\u207b\u00b9\u201d:<\/strong>
    This is false<\/strong>. The C\u2013H stretch from sp\u00b2-hybridized carbon atoms<\/strong> appears just above 3000 cm\u207b\u00b9<\/strong>, not below.<\/li>\n<\/ol>\n\n\n\n

    Thus, the only correct statement<\/strong> about the IR spectrum of 2,3-dimethyl-2-butene is that it shows a C\u2013H stretch for sp\u00b2\u2013hybridized carbon<\/strong> at around 3100 cm\u207b\u00b9<\/strong>.<\/p>\n\n\n\n

    \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

    What is true about the IR spectrum of 2,3-dimethyl-2-butene? There will be no peak (C-=C) at 1600-1700 cm-1 There will be a peak (C-H; sp2-s bond) at 3100 cm 1 There will be a peak (C-H; sp3-s bond) above 3000 cm There will be a peak (C-H; sp2-s bond) just below 3000 cm-1 None of […]<\/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-237627","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/237627","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=237627"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/237627\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=237627"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=237627"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=237627"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}