{"id":224150,"date":"2025-06-02T18:14:17","date_gmt":"2025-06-02T18:14:17","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=224150"},"modified":"2025-06-02T18:14:19","modified_gmt":"2025-06-02T18:14:19","slug":"ficks-law-of-dissolution-vs-noyes-whitney-equation","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/02\/ficks-law-of-dissolution-vs-noyes-whitney-equation\/","title":{"rendered":"Fick&#8217;s law of dissolution vs Noyes Whitney equation"},"content":{"rendered":"\n<p>Fick&#8217;s law of dissolution vs Noyes Whitney equation<\/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>Correct Answer:<\/strong><\/p>\n\n\n\n<p>Fick\u2019s Law of Diffusion is the fundamental principle underlying the <strong>Noyes-Whitney equation<\/strong>, which specifically describes the <strong>rate of dissolution of solids<\/strong> in liquids.<\/p>\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>Fick\u2019s Law of Diffusion and the Noyes-Whitney equation are closely related, but they serve different purposes in understanding solute transport and dissolution processes.<\/p>\n\n\n\n<p><strong>Fick\u2019s First Law<\/strong> of diffusion states that the rate of diffusion (flux) of a substance across a unit area is proportional to the concentration gradient: J=\u2212DdCdxJ = -D \\frac{dC}{dx}<\/p>\n\n\n\n<p>Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>JJ = diffusion flux<\/li>\n\n\n\n<li>DD = diffusion coefficient<\/li>\n\n\n\n<li>dC\/dxdC\/dx = concentration gradient<\/li>\n<\/ul>\n\n\n\n<p>Fick\u2019s law is a general law that applies to the movement of molecules in a medium due to concentration differences. It doesn&#8217;t account for the solid state of the solute or the interfacial area.<\/p>\n\n\n\n<p>On the other hand, the <strong>Noyes-Whitney equation<\/strong> is derived from Fick\u2019s law and specifically models <strong>the dissolution rate of a solid substance<\/strong> into a solvent: dCdt=DA(Cs\u2212C)h\\frac{dC}{dt} = \\frac{DA (C_s &#8211; C)}{h}<\/p>\n\n\n\n<p>Where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>dCdt\\frac{dC}{dt} = dissolution rate<\/li>\n\n\n\n<li>DD = diffusion coefficient<\/li>\n\n\n\n<li>AA = surface area of the dissolving solid<\/li>\n\n\n\n<li>CsC_s = saturation solubility of the solute<\/li>\n\n\n\n<li>CC = concentration of solute at time tt<\/li>\n\n\n\n<li>hh = thickness of the diffusion layer<\/li>\n<\/ul>\n\n\n\n<p>This equation applies Fick\u2019s principle to a <strong>solid-liquid interface<\/strong>, describing how a solute dissolves over time depending on surface area, solubility, and diffusion dynamics. The key assumption is that dissolution is diffusion-controlled \u2014 meaning the rate-limiting step is diffusion through a boundary layer.<\/p>\n\n\n\n<p>In summary, Fick&#8217;s law provides the theoretical framework for diffusion, while the Noyes-Whitney equation is a practical application of this theory to the pharmaceutical and chemical industries to predict dissolution rates of tablets and other solid dosage forms.<\/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-banner4-159.jpeg\" alt=\"\" class=\"wp-image-224151\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Fick&#8217;s law of dissolution vs Noyes Whitney equation The Correct Answer and Explanation is: Correct Answer: Fick\u2019s Law of Diffusion is the fundamental principle underlying the Noyes-Whitney equation, which specifically describes the rate of dissolution of solids in liquids. Explanation Fick\u2019s Law of Diffusion and the Noyes-Whitney equation are closely related, but they serve different [&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-224150","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/224150","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=224150"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/224150\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=224150"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=224150"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=224150"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}