{"id":213259,"date":"2025-05-10T06:14:20","date_gmt":"2025-05-10T06:14:20","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=213259"},"modified":"2025-05-10T06:14:24","modified_gmt":"2025-05-10T06:14:24","slug":"the-pkas-of-methanol-ch3oh-and-methanethiol-ch3sh-are-16-and-11-respectively","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/10\/the-pkas-of-methanol-ch3oh-and-methanethiol-ch3sh-are-16-and-11-respectively\/","title":{"rendered":"The pKa\u2019s of methanol (CH3OH) and methanethiol (CH3SH) are 16 and 11, respectively."},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">The pKa\u2019s of methanol (CH3OH) and methanethiol (CH3SH) are 16 and 11, respectively.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Which is more basic, KOCH3 or KSCH3?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-ast-global-color-0-color\">The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To determine which compound is more <strong>basic<\/strong> between <strong>KOCH\u2083 (potassium methoxide)<\/strong> and <strong>KSCH\u2083 (potassium methanethiolate)<\/strong>, we need to consider the <strong>pKa values<\/strong> of their conjugate acids: <strong>CH\u2083OH<\/strong> and <strong>CH\u2083SH<\/strong>, respectively.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Correct Answer: KOCH\u2083 is more basic than KSCH\u2083.<\/strong><\/h3>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Explanation:<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">In acid-base chemistry, <strong>basicity<\/strong> is closely tied to the <strong>stability of a conjugate acid<\/strong> and the <strong>strength of the conjugate base<\/strong>. A <strong>stronger base<\/strong> has a <strong>weaker conjugate acid<\/strong>, meaning the conjugate acid has a <strong>higher pKa<\/strong> value.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Let\u2019s compare the pKa values of the conjugate acids:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>CH\u2083OH (methanol)<\/strong> has a <strong>pKa of ~16<\/strong><\/li>\n\n\n\n<li><strong>CH\u2083SH (methanethiol)<\/strong> has a <strong>pKa of ~11<\/strong><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Since methanol has a <strong>higher pKa<\/strong>, it is a <strong>weaker acid<\/strong> than methanethiol. That means its conjugate base, <strong>CH\u2083O\u207b (methoxide)<\/strong>, is <strong>stronger<\/strong> (more basic) than <strong>CH\u2083S\u207b (methanethiolate)<\/strong>, the conjugate base of methanethiol.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is explained by the <strong>relative electronegativity and size of oxygen and sulfur<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Oxygen (in CH\u2083O\u207b) is <strong>more electronegative<\/strong> than sulfur and better at stabilizing a negative charge through <strong>electronegativity<\/strong>, but <strong>not<\/strong> as well via <strong>size\/diffuse orbitals<\/strong>.<\/li>\n\n\n\n<li>Sulfur (in CH\u2083S\u207b) is <strong>less electronegative<\/strong>, but its <strong>larger atomic radius<\/strong> spreads out the negative charge better, making CH\u2083S\u207b <strong>more stable<\/strong>, and therefore <strong>less reactive<\/strong>, i.e., <strong>a weaker base<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">So even though sulfur can better stabilize a negative charge, that <strong>very stability makes its conjugate base less basic<\/strong>\u2014because basicity is about <strong>reactivity and willingness to accept protons<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Thus, between KOCH\u2083 and KSCH\u2083:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>KOCH\u2083<\/strong> has the stronger base (CH\u2083O\u207b)<\/li>\n\n\n\n<li><strong>KSCH\u2083<\/strong> has the weaker base (CH\u2083S\u207b)<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Conclusion:<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>KOCH\u2083 (potassium methoxide)<\/strong> is <strong>more basic<\/strong> than <strong>KSCH\u2083 (potassium methanethiolate)<\/strong> because its conjugate acid has a higher pKa, meaning the base is stronger.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The pKa\u2019s of methanol (CH3OH) and methanethiol (CH3SH) are 16 and 11, respectively. Which is more basic, KOCH3 or KSCH3? The Correct Answer and Explanation is: To determine which compound is more basic between KOCH\u2083 (potassium methoxide) and KSCH\u2083 (potassium methanethiolate), we need to consider the pKa values of their conjugate acids: CH\u2083OH and CH\u2083SH, [&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-213259","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/213259","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=213259"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/213259\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=213259"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=213259"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=213259"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}