{"id":220824,"date":"2025-05-28T20:09:25","date_gmt":"2025-05-28T20:09:25","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=220824"},"modified":"2025-05-28T20:09:27","modified_gmt":"2025-05-28T20:09:27","slug":"write-the-hydrolytic-reaction-for-the-ion-when-it-acts-as","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/05\/28\/write-the-hydrolytic-reaction-for-the-ion-when-it-acts-as\/","title":{"rendered":"Write the hydrolytic reaction for the ion when it acts as"},"content":{"rendered":"\n

Hydrogen phosphate ion (HPO4-) is also an amphoteric molecule. Write the hydrolytic reaction for the ion when it acts as (a) an acid and (b) a base.<\/p>\n\n\n\n

The Correct Answer and Explanation is:<\/mark><\/strong><\/p>\n\n\n\n

Hydrolytic Reactions of Hydrogen Phosphate Ion (HPO\u2084\u00b2\u207b):<\/h3>\n\n\n\n

Hydrogen phosphate ion is amphoteric<\/strong>, meaning it can act as both an acid and a base depending on the surrounding chemical environment.<\/p>\n\n\n\n

(a) When HPO\u2084\u00b2\u207b acts as an acid<\/strong>:<\/h4>\n\n\n\n

It donates a proton (H\u207a) to water. HPO42\u2212+H2O\u21ccPO43\u2212+H3O+\\text{HPO}_4^{2-} + \\text{H}_2\\text{O} \\rightleftharpoons \\text{PO}_4^{3-} + \\text{H}_3\\text{O}^+<\/p>\n\n\n\n

(b) When HPO\u2084\u00b2\u207b acts as a base<\/strong>:<\/h4>\n\n\n\n

It accepts a proton (H\u207a) from water. HPO42\u2212+H2O\u21ccH2PO4\u2212+OH\u2212\\text{HPO}_4^{2-} + \\text{H}_2\\text{O} \\rightleftharpoons \\text{H}_2\\text{PO}_4^- + \\text{OH}^-<\/p>\n\n\n\n

\n\n\n\n

Explanation<\/h3>\n\n\n\n

The hydrogen phosphate ion (HPO\u2084\u00b2\u207b) is part of the phosphate buffer system and is amphoteric, which means it can function as either an acid or a base depending on its chemical surroundings. Amphoterism arises due to the presence of both a proton that can be donated and lone pairs that can accept a proton.<\/p>\n\n\n\n

In acidic conditions<\/strong>, where HPO\u2084\u00b2\u207b acts as a base<\/strong>, it accepts a proton from water. The water molecule donates a hydrogen ion (H\u207a), forming hydroxide (OH\u207b), while HPO\u2084\u00b2\u207b becomes dihydrogen phosphate (H\u2082PO\u2084\u207b). This reaction contributes to buffering against excess H\u207a<\/strong> in solution.<\/p>\n\n\n\n

Conversely, in basic conditions<\/strong>, HPO\u2084\u00b2\u207b acts as an acid<\/strong> by donating a proton to water. The water accepts the proton, forming a hydronium ion (H\u2083O\u207a), and HPO\u2084\u00b2\u207b is converted into phosphate ion (PO\u2084\u00b3\u207b). This action helps neutralize excess OH\u207b<\/strong> in the environment.<\/p>\n\n\n\n

This dual behavior is crucial in biological systems, especially in maintaining pH balance in blood and intracellular fluids. The phosphate buffer system, which includes H\u2082PO\u2084\u207b and HPO\u2084\u00b2\u207b, is effective in resisting pH changes because it can counter both acidic and basic shifts through reversible reactions.<\/p>\n\n\n\n

The acid dissociation constants<\/strong> (Ka) further support this behavior. H\u2082PO\u2084\u207b has a pKa of about 7.2, which is close to physiological pH, allowing the H\u2082PO\u2084\u207b\/HPO\u2084\u00b2\u207b pair to act as an effective buffer. The position of equilibrium in each reaction is determined by the pH of the solution, favoring the side that minimizes pH changes.<\/p>\n\n\n\n

Thus, HPO\u2084\u00b2\u207b plays a vital amphoteric and buffering role in both environmental and physiological chemistry.<\/p>\n\n\n\n

\"\"<\/figure>\n","protected":false},"excerpt":{"rendered":"

Hydrogen phosphate ion (HPO4-) is also an amphoteric molecule. Write the hydrolytic reaction for the ion when it acts as (a) an acid and (b) a base. The Correct Answer and Explanation is: Hydrolytic Reactions of Hydrogen Phosphate Ion (HPO\u2084\u00b2\u207b): Hydrogen phosphate ion is amphoteric, meaning it can act as both an acid and a […]<\/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-220824","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/220824","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=220824"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/220824\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=220824"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=220824"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=220824"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}