{"id":219853,"date":"2025-05-27T05:42:46","date_gmt":"2025-05-27T05:42:46","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=219853"},"modified":"2025-05-27T05:42:48","modified_gmt":"2025-05-27T05:42:48","slug":"the-boiling-point-of-ch4-is-lower-than-the-boiling-point-of-sih4-whereas-the-boiling-point-of-nh3-is-higher-than-the-boiling-point-of-ph3","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/27\/the-boiling-point-of-ch4-is-lower-than-the-boiling-point-of-sih4-whereas-the-boiling-point-of-nh3-is-higher-than-the-boiling-point-of-ph3\/","title":{"rendered":"The boiling point of CH4 is lower than the boiling point of SiH4, whereas the boiling point of NH3 is higher than the boiling point of PH3"},"content":{"rendered":"\n<p>The boiling point of CH4 is lower than the boiling point of SiH4, whereas the boiling point of NH3 is higher than the boiling point of PH3. The lower boiling point of CH4 compared to SiH4 is expected because of its lower molecular weight.<\/p>\n\n\n\n<p>is expected because of the hydrogen bonding in SiH4.<br>cannot be explained.<br>is expected because of the stronger induced dipole forces in CH4.<br>is expected because of the stronger dipole forces in SiH4.<\/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>The correct answer is:<\/p>\n\n\n\n<p><strong>is expected because of its lower molecular weight.<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Explanation <\/h3>\n\n\n\n<p>Boiling point trends in covalent molecules can often be explained by examining the <strong>intermolecular forces<\/strong> (IMFs) acting between the molecules. These include London dispersion forces (induced dipole-induced dipole), dipole-dipole interactions, and hydrogen bonding.<\/p>\n\n\n\n<p><strong>Methane (CH\u2084)<\/strong> and <strong>silane (SiH\u2084)<\/strong> are both group 14 hydrides with tetrahedral geometry and are <strong>nonpolar<\/strong> molecules. Since they lack a permanent dipole and do not engage in hydrogen bonding (hydrogen bonding requires highly electronegative atoms like N, O, or F), the <strong>dominant intermolecular force<\/strong> in both is <strong>London dispersion forces<\/strong>.<\/p>\n\n\n\n<p>London dispersion forces increase with <strong>molecular size and mass<\/strong> because larger molecules have more electrons and are more polarizable. CH\u2084 has a molar mass of about <strong>16 g\/mol<\/strong>, while SiH\u2084 has a molar mass of about <strong>32 g\/mol<\/strong>. Because SiH\u2084 is heavier and has more electrons than CH\u2084, its dispersion forces are stronger, leading to a <strong>higher boiling point<\/strong>.<\/p>\n\n\n\n<p>This makes the <strong>lower boiling point of CH\u2084 compared to SiH\u2084 expected due to its lower molecular weight and weaker dispersion forces<\/strong>.<\/p>\n\n\n\n<p>Regarding the <strong>incorrect options<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u201c<strong>Is expected because of the hydrogen bonding in SiH\u2084<\/strong>\u201d is incorrect: SiH\u2084 does <strong>not<\/strong> exhibit hydrogen bonding, as silicon is not electronegative enough.<\/li>\n\n\n\n<li>\u201c<strong>Cannot be explained<\/strong>\u201d is incorrect: the difference can be clearly explained by London dispersion forces and molecular weight.<\/li>\n\n\n\n<li>\u201c<strong>Is expected because of the stronger induced dipole forces in CH\u2084<\/strong>\u201d is incorrect: CH\u2084 has <strong>weaker<\/strong>, not stronger, induced dipole (dispersion) forces than SiH\u2084.<\/li>\n\n\n\n<li>\u201c<strong>Is expected because of the stronger dipole forces in SiH\u2084<\/strong>\u201d is also incorrect: SiH\u2084 is <strong>nonpolar<\/strong>, so dipole-dipole forces are not relevant.<\/li>\n<\/ul>\n\n\n\n<p>In conclusion, the boiling point trend between CH\u2084 and SiH\u2084 is best explained by their <strong>molecular weights and corresponding London dispersion forces<\/strong>.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img decoding=\"async\" src=\"https:\/\/learnexams.com\/blog\/wp-content\/uploads\/2025\/05\/learnexams-banner6-58.jpeg\" alt=\"\" class=\"wp-image-219854\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>The boiling point of CH4 is lower than the boiling point of SiH4, whereas the boiling point of NH3 is higher than the boiling point of PH3. The lower boiling point of CH4 compared to SiH4 is expected because of its lower molecular weight. is expected because of the hydrogen bonding in SiH4.cannot be explained.is [&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-219853","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/219853","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=219853"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/219853\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=219853"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=219853"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=219853"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}