{"id":232319,"date":"2025-06-11T22:56:44","date_gmt":"2025-06-11T22:56:44","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=232319"},"modified":"2025-06-11T22:56:46","modified_gmt":"2025-06-11T22:56:46","slug":"choose-the-correct-compound-for-the-given-ir-spectrum","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/11\/choose-the-correct-compound-for-the-given-ir-spectrum\/","title":{"rendered":"Choose the correct compound for the given IR spectrum."},"content":{"rendered":"\n

Choose the correct compound for the given IR spectrum. % Transmittance 100 80 60 40 20 0 4000 3500 3000 2500 2000 A) NH2 B) C) D) OH Wavenumber (cm
) 1500 1000<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

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

The correct compound is D) 4-Methyl-1-pentanol<\/strong>.<\/p>\n\n\n\n

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

To identify the correct compound, we must analyze the key absorption bands in the provided Infrared (IR) spectrum and match them to the functional groups present in the given options.<\/p>\n\n\n\n

    \n
  1. O-H Stretch (Alcohol):<\/strong>\u00a0The most prominent feature in the spectrum is the very broad, strong absorption band centered at approximately 3300 cm\u207b\u00b9. This is the characteristic signal for the O-H stretching vibration of an alcohol. The significant broadening of this peak is due to intermolecular hydrogen bonding between alcohol molecules.<\/li>\n\n\n\n
  2. C-H Stretch (Alkane):<\/strong>\u00a0The sharp, strong peaks observed just below 3000 cm\u207b\u00b9 (specifically in the 2850-2960 cm\u207b\u00b9 range) are characteristic of C-H stretching vibrations from sp\u00b3-hybridized carbons, indicating the presence of an alkane-like (saturated) carbon skeleton.<\/li>\n\n\n\n
  3. C-O Stretch:<\/strong>\u00a0In the fingerprint region, there is a distinct peak around 1050 cm\u207b\u00b9. This absorption is consistent with the C-O stretching vibration of a primary alcohol, which typically appears between 1000-1250 cm\u207b\u00b9.<\/li>\n<\/ol>\n\n\n\n

    Now, let’s evaluate the options based on this analysis:<\/p>\n\n\n\n

      \n
    • A) Butylamine:<\/strong>\u00a0This is a primary amine. A primary amine (-NH\u2082) would show two medium, sharp N-H stretching peaks in the 3300-3500 cm\u207b\u00b9 region, not a single, very broad peak like the one observed. Therefore, this option is incorrect.<\/li>\n\n\n\n
    • B) 1-Pentene:<\/strong>\u00a0This is an alkene. It would exhibit a C=C stretching peak around 1640 cm\u207b\u00b9 and, importantly, a C-H stretching peak from the sp\u00b2 carbons of the double bond\u00a0above<\/em>\u00a03000 cm\u207b\u00b9. Neither of these key signals is present in the spectrum. Thus, this option is incorrect.<\/li>\n\n\n\n
    • C) Pentane:<\/strong>\u00a0This is an alkane. Its spectrum would only show sp\u00b3 C-H stretching peaks below 3000 cm\u207b\u00b9 and C-H bending peaks in the fingerprint region. It would not have the strong, broad O-H absorption at 3300 cm\u207b\u00b9. Therefore, this option is incorrect.<\/li>\n\n\n\n
    • D) 4-Methyl-1-pentanol:<\/strong>\u00a0This compound is a primary alcohol with a saturated alkyl chain. It contains an O-H group, which accounts for the broad peak at ~3300 cm\u207b\u00b9. It has several sp\u00b3 C-H bonds, matching the strong peaks below 3000 cm\u207b\u00b9. Finally, as a primary alcohol, it has a C-O bond, which corresponds to the peak observed at ~1050 cm\u207b\u00b9. This structure is a perfect match for all the major features of the given IR spectrum.<\/li>\n<\/ul>\n\n\n\n
      \"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

      Choose the correct compound for the given IR spectrum. % Transmittance 100 80 60 40 20 0 4000 3500 3000 2500 2000 A) NH2 B) C) D) OH Wavenumber (cm) 1500 1000 The Correct Answer and Explanation is: The correct compound is D) 4-Methyl-1-pentanol. Explanation To identify the correct compound, we must analyze the key absorption […]<\/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-232319","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/232319","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=232319"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/232319\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=232319"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=232319"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=232319"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}