{"id":238983,"date":"2025-06-18T14:24:36","date_gmt":"2025-06-18T14:24:36","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=238983"},"modified":"2025-06-18T14:24:38","modified_gmt":"2025-06-18T14:24:38","slug":"which-of-the-following-0-5-m-aqueous-salt-solutions-will-have-a-ph-of-7-0-at-lif-rbbr-naclo4-nh4cl","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/06\/18\/which-of-the-following-0-5-m-aqueous-salt-solutions-will-have-a-ph-of-7-0-at-lif-rbbr-naclo4-nh4cl\/","title":{"rendered":"Which of the following 0.5 M aqueous salt solutions will have a pH of 7.0 at LiF RbBr NaClO4 NH4Cl"},"content":{"rendered":"\n<p><br> Which of the following 0.5 M aqueous salt solutions will have a pH of 7.0 at LiF RbBr NaClO4 NH4Cl A) LiF only B) NaClO4 only C) LiF and RbBr D) RbBr and NaClO4 &lt;&#8212;&#8212;&#8212;&#8212; E) NH4Cl only Answer: D My question: I understand that LiF is a strong base + weak acid, so it is not neutral. I also understand that NH4Cl is a weak base and strong acid, so it is not neutral. I understand that NaClO4 is a strong base and a strong acid, so it is neutral. But for RbBr, Br is a strong acid, so why is Rb considered, I guess in this case, to be a strong base? I thought 1A elements were NEUTRAL? Can someone please explain to me the conditions when 1a\/1b ions are neutral and when they are considered basic? Is it (aq) vs salt? Ahhhhhhhhhhhhhhh help, thanks<\/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>You&#8217;re asking an excellent and nuanced question about salt solutions and their pH behavior in water. Let\u2019s break it down clearly:<\/p>\n\n\n\n<p>The key to predicting whether a salt solution is <strong>acidic<\/strong>, <strong>basic<\/strong>, or <strong>neutral<\/strong> lies in understanding <strong>how the ions from the salt interact with water (hydrolyze)<\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Group 1A and 2A Metals:<\/h3>\n\n\n\n<p>Cations from <strong>Group 1A (alkali metals)<\/strong> and <strong>Group 2A (alkaline earth metals)<\/strong> like <strong>Li\u207a, Na\u207a, K\u207a, Rb\u207a, Ca\u00b2\u207a, Sr\u00b2\u207a<\/strong>, etc., <strong>do not hydrolyze<\/strong> in water. They are <strong>spectator ions<\/strong>. They come from <strong>strong bases<\/strong> like NaOH or RbOH, which fully dissociate and <strong>do not react with water<\/strong>, so they <strong>do not affect pH<\/strong>. That means:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Rb\u207a<\/strong> is <strong>neutral<\/strong>, not basic.<\/li>\n\n\n\n<li>Same goes for <strong>Li\u207a<\/strong>, <strong>Na\u207a<\/strong>, etc.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Anion Consideration:<\/h3>\n\n\n\n<p>Now check the <strong>anion<\/strong> of the salt.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Br\u207b<\/strong> comes from <strong>HBr<\/strong>, a <strong>strong acid<\/strong>. Strong acid conjugate bases like Br\u207b do <strong>not hydrolyze<\/strong>, so they are also <strong>neutral<\/strong>.<\/li>\n\n\n\n<li><strong>ClO\u2084\u207b<\/strong> comes from <strong>HClO\u2084<\/strong>, another strong acid \u2014 also <strong>neutral<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p>So, if both the <strong>cation<\/strong> and <strong>anion<\/strong> of a salt come from <strong>strong acid and strong base<\/strong>, the resulting solution is <strong>neutral (pH = 7)<\/strong>.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Now, Your Specific Case:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>LiF<\/strong> \u2192 Li\u207a (neutral) and F\u207b (from HF, a <strong>weak acid<\/strong>) \u2192 <strong>F\u207b hydrolyzes<\/strong>, so <strong>basic<\/strong> solution.<\/li>\n\n\n\n<li><strong>RbBr<\/strong> \u2192 Rb\u207a (neutral) and Br\u207b (neutral) \u2192 <strong>neutral<\/strong> solution.<\/li>\n\n\n\n<li><strong>NaClO\u2084<\/strong> \u2192 Na\u207a (neutral) and ClO\u2084\u207b (neutral) \u2192 <strong>neutral<\/strong> solution.<\/li>\n\n\n\n<li><strong>NH\u2084Cl<\/strong> \u2192 NH\u2084\u207a (from a <strong>weak base<\/strong>, NH\u2083) and Cl\u207b (neutral) \u2192 NH\u2084\u207a hydrolyzes \u2192 <strong>acidic<\/strong> solution.<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">Conclusion:<\/h3>\n\n\n\n<p>The correct answer is <strong>D) RbBr and NaClO\u2084<\/strong>, because <strong>both their ions are neutral<\/strong>, and thus their 0.5 M aqueous solutions will have <strong>pH = 7.0<\/strong>.<\/p>\n\n\n\n<p>Your confusion came from thinking 1A metals can be basic \u2014 but they are actually <strong>neutral<\/strong> in water. The only thing that makes a salt solution acidic or basic is <strong>whether either the cation or anion hydrolyzes<\/strong>, not whether the salt is aqueous or solid.<\/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-banner8-1129.jpeg\" alt=\"\" class=\"wp-image-238984\"\/><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Which of the following 0.5 M aqueous salt solutions will have a pH of 7.0 at LiF RbBr NaClO4 NH4Cl A) LiF only B) NaClO4 only C) LiF and RbBr D) RbBr and NaClO4 &lt;&#8212;&#8212;&#8212;&#8212; E) NH4Cl only Answer: D My question: I understand that LiF is a strong base + weak acid, so it [&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-238983","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/238983","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=238983"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/238983\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=238983"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=238983"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=238983"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}