{"id":181329,"date":"2025-01-10T10:21:13","date_gmt":"2025-01-10T10:21:13","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=181329"},"modified":"2025-01-10T10:21:16","modified_gmt":"2025-01-10T10:21:16","slug":"explain-why-the-agcl-precipitate-dissolved-when-nhz-was-added","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/01\/10\/explain-why-the-agcl-precipitate-dissolved-when-nhz-was-added\/","title":{"rendered":"Explain why the AgCl precipitate dissolved when NHz was added"},"content":{"rendered":"\n

Explain why the AgCl precipitate dissolved when NHz was added. Use the following equilibria in framing your answer. (1) Ag+ (aq) + Cl(aq) = AgCl(s) (2) Ag(aq) + 2NH3(aq) 5 Ag(NH3)2+ (aq) 2. Explain why the AgCl re-precipitated upon addition of HNO3. Consider the above equilibria [i.e. Reactions (1) & (2) ] and recall that: (3) NH3(aq) + H<\/em>(aq) = NH.+ (aq)<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

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

Explanation of the Dissolution and Re-precipitation of AgCl:<\/h3>\n\n\n\n
    \n
  1. Dissolution of AgCl when NH\u2083 is added:<\/strong><\/li>\n<\/ol>\n\n\n\n

    The dissolution of AgCl occurs because of the complexation of Ag\u207a ions with ammonia (NH\u2083). Let’s look at the chemical reactions involved:<\/p>\n\n\n\n

      \n
    • Reaction (1):<\/strong>
      [ \\text{Ag}^+(aq) + \\text{Cl}^-(aq) \\rightleftharpoons \\text{AgCl(s)} ]
      In this equilibrium, silver chloride (AgCl) is formed from its ions in the solution. When NH\u2083 is added, it reacts with Ag\u207a ions, forming a complex ion, (\\text{Ag(NH\u2083)_2}^+), as shown in Reaction (2).<\/li>\n\n\n\n
    • Reaction (2):<\/strong>
      [ \\text{Ag}^+(aq) + 2\\text{NH\u2083}(aq) \\rightleftharpoons \\text{Ag(NH\u2083)_2}^+(aq) ]
      The addition of ammonia shifts this equilibrium to the right, increasing the concentration of (\\text{Ag(NH\u2083)_2}^+) in solution and decreasing the concentration of free Ag\u207a ions.<\/li>\n<\/ul>\n\n\n\n

      According to Le Chatelier\u2019s Principle, as the concentration of Ag\u207a ions decreases due to their complexation with NH\u2083, the equilibrium of Reaction (1) shifts to the right to counteract this decrease, leading to the dissolution of solid AgCl. Therefore, the AgCl precipitate dissolves in the presence of ammonia due to the formation of the soluble (\\text{Ag(NH\u2083)_2}^+) complex.<\/p>\n\n\n\n

        \n
      1. Re-precipitation of AgCl upon the addition of HNO\u2083:<\/strong><\/li>\n<\/ol>\n\n\n\n

        When HNO\u2083 is added, it introduces H\u207a ions into the solution. These H\u207a ions can react with the ammonia in solution as shown in Reaction (3):<\/p>\n\n\n\n

          \n
        • Reaction (3):<\/strong>
          [ \\text{NH\u2083}(aq) + \\text{H}^+(aq) \\rightleftharpoons \\text{NH\u2084}^+(aq) ]
          The added H\u207a ions protonate the ammonia molecules, converting them into ammonium ions (NH\u2084\u207a). This reduces the concentration of free NH\u2083 in the solution, shifting the equilibrium in Reaction (2) to the left. As a result, the (\\text{Ag(NH\u2083)_2}^+) complex breaks down, and Ag\u207a ions are released back into the solution.<\/li>\n\n\n\n
        • Re-establishment of Reaction (1):<\/strong>
          As the concentration of Ag\u207a ions increases, the equilibrium of Reaction (1) shifts to the left, causing AgCl to precipitate again from the solution. Thus, the re-precipitation of AgCl occurs because the free Ag\u207a ions, now present in higher concentration due to the breakdown of the complex, combine with the chloride ions to form solid AgCl.<\/li>\n<\/ul>\n\n\n\n

          In summary:<\/p>\n\n\n\n

            \n
          • NH\u2083<\/strong> causes Ag\u207a ions to form a soluble complex, leading to the dissolution of AgCl.<\/li>\n\n\n\n
          • HNO\u2083<\/strong> introduces H\u207a, which reduces the availability of NH\u2083, causing Ag\u207a to be released and leading to the re-precipitation of AgCl.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

            Explain why the AgCl precipitate dissolved when NHz was added. Use the following equilibria in framing your answer. (1) Ag+ (aq) + Cl(aq) = AgCl(s) (2) Ag(aq) + 2NH3(aq) 5 Ag(NH3)2+ (aq) 2. Explain why the AgCl re-precipitated upon addition of HNO3. Consider the above equilibria [i.e. Reactions (1) & (2) ] and recall that: […]<\/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-181329","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/181329","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=181329"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/181329\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=181329"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=181329"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=181329"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}