onsider the IR spectra for 9-flueorenol that are shown below. Which compound belongs to spectrum A? Which compound belongs to spectrum B? a) in the functional group region of the 9-fluorenone spectrum, identify the absorptions associated with the carbonyl group and with the aromatic rings. b) in the functional group region of the 9-fluorenol spectrum, specify the functional group that is associated with the broad absorption at about 3100-3400 cm^-1.<\/p>\n\n\n\n
The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n To correctly assign IR spectra to 9-fluorenol<\/strong> and 9-fluorenone<\/strong>, we must understand the characteristic IR absorption bands of their functional groups.<\/p>\n\n\n\n Infrared (IR) spectroscopy is a powerful tool for identifying functional groups in organic compounds. Each type of bond absorbs IR radiation at specific frequencies, measured in wavenumbers (cm\u207b\u00b9)<\/strong>. Let\u2019s examine each compound and their expected IR features:<\/p>\n\n\n\n 9-Fluorenone<\/strong> contains a ketone functional group (C=O)<\/strong> and aromatic rings<\/strong>.<\/p>\n\n\n\n Therefore, the presence of a strong C=O peak<\/strong> and aromatic C=C peaks<\/strong> confirms that Spectrum A is 9-fluorenone<\/strong>.<\/p>\n\n\n\n 9-Fluorenol<\/strong> is an alcohol<\/strong>, with a hydroxyl group (-OH) at the 9-position on the fluorene skeleton.<\/p>\n\n\n\n Importantly, Spectrum B lacks the strong C=O peak<\/strong>, differentiating it from 9-fluorenone.<\/p>\n\n\n\n Understanding the position and shape of these peaks allows chemists to reliably determine the identity of compounds using IR spectra.<\/p>\n","protected":false},"excerpt":{"rendered":" onsider the IR spectra for 9-flueorenol that are shown below. Which compound belongs to spectrum A? Which compound belongs to spectrum B? a) in the functional group region of the 9-fluorenone spectrum, identify the absorptions associated with the carbonyl group and with the aromatic rings. b) in the functional group region of the 9-fluorenol spectrum, […]<\/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-215671","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/215671","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=215671"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/215671\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=215671"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=215671"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=215671"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n\n\n\nCorrect Answer:<\/strong><\/h3>\n\n\n\n
\n
\n\n\n\nExplanation (300+ words):<\/strong><\/h3>\n\n\n\n
\n\n\n\na) 9-Fluorenone (Spectrum A)<\/strong><\/h3>\n\n\n\n
\n
The strong absorption<\/strong> around 1710\u20131740 cm\u207b\u00b9<\/strong> is characteristic of a C=O bond<\/strong> found in ketones. In aromatic ketones like 9-fluorenone, this usually appears at around 1715 cm\u207b\u00b9<\/strong>. This peak is sharp and intense<\/strong>, making it one of the easiest to identify in the IR spectrum.<\/li>\n\n\n\n
These appear as multiple peaks<\/strong> in the region of 1450\u20131600 cm\u207b\u00b9<\/strong>, due to the conjugated \u03c0-system in the aromatic rings. Although weaker than the carbonyl peak, their pattern is typical for aromatic compounds.<\/li>\n<\/ol>\n\n\n\n
\n\n\n\nb) 9-Fluorenol (Spectrum B)<\/strong><\/h3>\n\n\n\n
\n
A broad absorption<\/strong> between 3200\u20133600 cm\u207b\u00b9<\/strong> is characteristic of hydrogen-bonded O\u2013H stretching<\/strong>. This is a hallmark of alcohols. In 9-fluorenol, this peak typically appears between 3100\u20133400 cm\u207b\u00b9<\/strong>, confirming the presence of an -OH group.<\/li>\n\n\n\n
Similar to 9-fluorenone, 9-fluorenol also has aromatic rings, showing medium-to-weak peaks around 1450\u20131600 cm\u207b\u00b9<\/strong> (C=C stretching) and around 3030 cm\u207b\u00b9<\/strong> for aromatic C\u2013H stretches.<\/li>\n<\/ol>\n\n\n\n
\n\n\n\nConclusion:<\/strong><\/h3>\n\n\n\n
\n