Enough of a monoprotic acid is dissolved in water to produce a 0.0192 M solution. The pH of the resulting solution is 2.53. Calculate the Ka for the acid.<\/p>\n\n\n\n
The correct answer and explanation is :<\/strong><\/mark><\/p>\n\n\n\n To calculate the acid dissociation constant (Ka) for the monoprotic acid, we need to use the given information: the concentration of the acid (0.0192 M) and the pH of the solution (2.53). The relationship between the pH and the concentration of hydrogen ions (([H^+])) is crucial to solve for Ka.<\/p>\n\n\n\n The pH of a solution is defined as:<\/p>\n\n\n\n [ Rearranging this equation to solve for ([H^+]):<\/p>\n\n\n\n [ For a monoprotic acid (HA), the dissociation in water can be written as:<\/p>\n\n\n\n [ Initially, the concentration of the acid, ([HA]_0), is 0.0192 M, and the concentration of ([H^+]) and ([A^-]) are both initially 0 M.<\/p>\n\n\n\n After dissociation, let (x) represent the concentration of the dissociated hydrogen ions and conjugate base ions. From the pH calculation, we already know that ([H^+] = 2.95 \\times 10^{-3} \\, \\text{M}), so:<\/p>\n\n\n\n [ Thus, at equilibrium:<\/p>\n\n\n\n [ [ The acid dissociation constant (K_a) is given by the equation:<\/p>\n\n\n\n [ Substitute the values:<\/p>\n\n\n\n [ The acid dissociation constant (Ka) for the monoprotic acid is approximately (5.36 \\times 10^{-4}).<\/p>\n\n\n\n This process involves using the relationship between pH and the hydrogen ion concentration to find the degree of dissociation, and from there, we can calculate the (K_a) value. It demonstrates how pH provides valuable insight into the dissociation equilibrium of acids in solution.<\/p>\n","protected":false},"excerpt":{"rendered":" Enough of a monoprotic acid is dissolved in water to produce a 0.0192 M solution. The pH of the resulting solution is 2.53. Calculate the Ka for the acid. The correct answer and explanation is : To calculate the acid dissociation constant (Ka) for the monoprotic acid, we need to use the given information: the […]<\/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-209786","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/209786","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=209786"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/209786\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=209786"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=209786"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=209786"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Step 1: Calculate ([H^+])<\/h3>\n\n\n\n
\\text{pH} = -\\log [H^+]
]<\/p>\n\n\n\n
[H^+] = 10^{-\\text{pH}} = 10^{-2.53} \\approx 2.95 \\times 10^{-3} \\, \\text{M}
]<\/p>\n\n\n\nStep 2: Set up the dissociation equation<\/h3>\n\n\n\n
HA \\rightleftharpoons H^+ + A^-
]<\/p>\n\n\n\n
x = [H^+] = 2.95 \\times 10^{-3} \\, \\text{M}
]<\/p>\n\n\n\n
[HA] = [HA]_0 – x = 0.0192 – 2.95 \\times 10^{-3} \\approx 0.01625 \\, \\text{M}
]<\/p>\n\n\n\n
[A^-] = x = 2.95 \\times 10^{-3} \\, \\text{M}
]<\/p>\n\n\n\nStep 3: Write the expression for (K_a)<\/h3>\n\n\n\n
K_a = \\frac{[H^+][A^-]}{[HA]}
]<\/p>\n\n\n\n
K_a = \\frac{(2.95 \\times 10^{-3})(2.95 \\times 10^{-3})}{0.01625} \\approx \\frac{8.70 \\times 10^{-6}}{0.01625} \\approx 5.36 \\times 10^{-4}
]<\/p>\n\n\n\nConclusion<\/h3>\n\n\n\n