{"id":234540,"date":"2025-06-14T08:16:15","date_gmt":"2025-06-14T08:16:15","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=234540"},"modified":"2025-06-14T08:16:17","modified_gmt":"2025-06-14T08:16:17","slug":"show-the-ir-mass-and-nmr-spectrum-of-trans-cinnamic-acid-with-brief-explanations","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/14\/show-the-ir-mass-and-nmr-spectrum-of-trans-cinnamic-acid-with-brief-explanations\/","title":{"rendered":"Show the IR, Mass and NMR spectrum of trans-cinnamic acid with brief explanations."},"content":{"rendered":"\n<p>Show the IR, Mass and NMR spectrum of trans-cinnamic acid with brief explanations.<\/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><strong>Spectral Analysis of Trans-Cinnamic Acid<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>1. Infrared (IR) Spectrum of Trans-Cinnamic Acid<\/strong><\/h3>\n\n\n\n<p><strong>Key IR Absorptions:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Broad O\u2013H stretch (carboxylic acid): ~2500\u20133300 cm\u207b\u00b9<\/li>\n\n\n\n<li>C=O stretch (carboxylic acid): ~1700 cm\u207b\u00b9<\/li>\n\n\n\n<li>Aromatic C=C stretch: ~1600, 1500 cm\u207b\u00b9<\/li>\n\n\n\n<li>C\u2013H stretch (sp\u00b2, alkene and aromatic): ~3020\u20133100 cm\u207b\u00b9<\/li>\n\n\n\n<li>C\u2013H stretch (sp\u00b3, alkyl): ~2850\u20132960 cm\u207b\u00b9<\/li>\n<\/ul>\n\n\n\n<p>The IR spectrum prominently displays a very broad and intense O\u2013H stretch due to hydrogen bonding of the carboxylic acid. The strong, sharp C=O stretch near 1700 cm\u207b\u00b9 confirms the presence of a carbonyl group. The aromatic and alkene C=C bonds produce medium intensity bands near 1600 and 1500 cm\u207b\u00b9.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>2. Mass Spectrum of Trans-Cinnamic Acid<\/strong><\/h3>\n\n\n\n<p><strong>Molecular formula:<\/strong> C\u2089H\u2088O\u2082<br><strong>Molecular weight:<\/strong> 148 g\/mol<br><strong>Key peaks:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>m\/z 148<\/strong> \u2013 Molecular ion peak [M\u207a]<\/li>\n\n\n\n<li><strong>m\/z 103<\/strong> \u2013 Base peak, likely from loss of COOH (\u201345)<\/li>\n\n\n\n<li><strong>m\/z 77<\/strong> \u2013 Benzyl fragment (C\u2086H\u2085\u207a)<\/li>\n<\/ul>\n\n\n\n<p>The molecular ion at m\/z 148 confirms the intact molecular weight. The base peak at m\/z 103 results from fragmentation of the carboxylic acid group. The phenyl ring cleavage gives the stable benzyl cation at m\/z 77.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>3. Proton NMR (\u00b9H NMR) Spectrum of Trans-Cinnamic Acid (in CDCl\u2083)<\/strong><\/h3>\n\n\n\n<p><strong>Key signals:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u03b4 12.0 ppm \u2013 1H, broad singlet (carboxylic acid proton, \u2013COOH)<\/li>\n\n\n\n<li>\u03b4 7.2\u20137.5 ppm \u2013 5H, multiplet (aromatic protons, phenyl ring)<\/li>\n\n\n\n<li>\u03b4 6.3\u20137.0 ppm \u2013 2H, doublets (trans-alkene protons, \u2013CH=CH\u2013)<\/li>\n<\/ul>\n\n\n\n<p>The acidic proton of the carboxylic group appears far downfield due to deshielding. The aromatic protons give a multiplet centered near 7.3 ppm. The vinyl protons on the alkene show trans coupling (J \u2248 16 Hz), giving two doublets with a chemical shift difference due to their differing electronic environments.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Conclusion<\/h3>\n\n\n\n<p>The combined IR, mass, and NMR spectra provide clear evidence for the functional groups present in trans-cinnamic acid, including the phenyl ring, carboxylic acid group, and the trans-configured alkene. Each technique contributes complementary structural information for compound confirmation.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/06\/learnexams-banner8-433.jpeg\" alt=\"\" class=\"wp-image-234541\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Show the IR, Mass and NMR spectrum of trans-cinnamic acid with brief explanations. The Correct Answer and Explanation is: Spectral Analysis of Trans-Cinnamic Acid 1. Infrared (IR) Spectrum of Trans-Cinnamic Acid Key IR Absorptions: The IR spectrum prominently displays a very broad and intense O\u2013H stretch due to hydrogen bonding of the carboxylic acid. The [&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-234540","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/234540","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=234540"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/234540\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=234540"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=234540"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=234540"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}