{"id":27444,"date":"2025-06-19T22:58:43","date_gmt":"2025-06-19T22:58:43","guid":{"rendered":"https:\/\/gaviki.com\/blog\/?p=27444"},"modified":"2025-06-19T22:58:48","modified_gmt":"2025-06-19T22:58:48","slug":"find-the-hydrogen-deficiency-index-hdi-of-each-molecular-formula-given-below-5-points","status":"publish","type":"post","link":"https:\/\/gaviki.com\/blog\/find-the-hydrogen-deficiency-index-hdi-of-each-molecular-formula-given-below-5-points\/","title":{"rendered":"Find the hydrogen deficiency index (HDI) of each molecular formula given below (5 points)"},"content":{"rendered":"\n<p>Find the hydrogen deficiency index (HDI) of each molecular formula given below (5 points): a. C12H18 b. C5H5Br2NO<\/p>\n\n\n\n<p><mark style=\"background-color:rgba(0, 0, 0, 0)\" class=\"has-inline-color has-vivid-cyan-blue-color\"><strong>The correct answer and explanation is:<\/strong><\/mark><\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Hydrogen Deficiency Index (HDI) \/ Degree of Unsaturation<\/strong><\/h3>\n\n\n\n<p>The <strong>Hydrogen Deficiency Index (HDI)<\/strong> tells us how many rings or multiple bonds (double or triple) are present in a molecule. Each degree of unsaturation corresponds to:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>1 ring<\/li>\n\n\n\n<li>1 double bond<\/li>\n\n\n\n<li>1 triple bond = 2 degrees<\/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\"><strong>HDI Formula<\/strong>:<\/h3>\n\n\n\n<p>For a molecular formula <strong>C\u2093H\u1d67N\ud835\udccfO\u2090X\u1d66<\/strong>, where:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>C = carbon atoms<\/li>\n\n\n\n<li>H = hydrogen atoms<\/li>\n\n\n\n<li>N = nitrogen atoms<\/li>\n\n\n\n<li>O = oxygen atoms<\/li>\n\n\n\n<li>X = halogens (F, Cl, Br, I)<\/li>\n<\/ul>\n\n\n\n<p>The formula is: HDI=2C+2+N\u2212H\u2212X2\\text{HDI} = \\frac{2C + 2 + N &#8211; H &#8211; X}{2}<\/p>\n\n\n\n<p><em>Note<\/em>: Oxygen does <strong>not<\/strong> affect the HDI and is ignored in the calculation.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>a. C\u2081\u2082H\u2081\u2088<\/strong><\/h3>\n\n\n\n<p>HDI=2(12)+2\u2212182=24+2\u2212182=82=4\\text{HDI} = \\frac{2(12) + 2 &#8211; 18}{2} = \\frac{24 + 2 &#8211; 18}{2} = \\frac{8}{2} = \\boxed{4}<\/p>\n\n\n\n<p><strong>Explanation<\/strong>:<br>This molecule has 4 degrees of unsaturation. That means it could have:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>4 double bonds, or<\/li>\n\n\n\n<li>2 double bonds and 2 rings, or<\/li>\n\n\n\n<li>1 ring and 3 double bonds, etc.<br>The actual structure would tell us which combination is present.<\/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\"><strong>b. C\u2085H\u2085Br\u2082NO<\/strong><\/h3>\n\n\n\n<p>Bromine (Br) is a halogen, so we treat it as <strong>X = 2<\/strong>, and N = 1. HDI=2(5)+2+1\u22125\u221222=10+2+1\u22125\u221222=62=3\\text{HDI} = \\frac{2(5) + 2 + 1 &#8211; 5 &#8211; 2}{2} = \\frac{10 + 2 + 1 &#8211; 5 &#8211; 2}{2} = \\frac{6}{2} = \\boxed{3}<\/p>\n\n\n\n<p><strong>Explanation<\/strong>:<br>This compound has 3 degrees of unsaturation. This could mean:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>A benzene ring (which is 4), but since this is only 3, maybe<\/li>\n\n\n\n<li>1 ring and 1 double bond, or<\/li>\n\n\n\n<li>1 triple bond, or<\/li>\n\n\n\n<li>3 double bonds.<\/li>\n<\/ul>\n\n\n\n<p>The presence of nitrogen and halogens hints it could be an aromatic or substituted ring structure.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">\u2705 <strong>Final Answers<\/strong>:<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>a. C\u2081\u2082H\u2081\u2088<\/strong> \u2192 <strong>HDI = 4<\/strong><\/li>\n\n\n\n<li><strong>b. C\u2085H\u2085Br\u2082NO<\/strong> \u2192 <strong>HDI = 3<\/strong><\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Find the hydrogen deficiency index (HDI) of each molecular formula given below (5 points): a. C12H18 b. C5H5Br2NO The correct answer and explanation is: Hydrogen Deficiency Index (HDI) \/ Degree of Unsaturation The Hydrogen Deficiency Index (HDI) tells us how many rings or multiple bonds (double or triple) are present in a molecule. Each degree [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-27444","post","type-post","status-publish","format-standard","hentry","category-quiz-questions"],"_links":{"self":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/27444","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/comments?post=27444"}],"version-history":[{"count":1,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/27444\/revisions"}],"predecessor-version":[{"id":27445,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/posts\/27444\/revisions\/27445"}],"wp:attachment":[{"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/media?parent=27444"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/categories?post=27444"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaviki.com\/blog\/wp-json\/wp\/v2\/tags?post=27444"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}