{"id":87665,"date":"2025-06-01T06:50:50","date_gmt":"2025-06-01T06:50:50","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=87665"},"modified":"2025-06-01T06:50:50","modified_gmt":"2025-06-01T06:50:50","slug":"dinitrogen-n%e2%82%82-and-dioxygen-o%e2%82%82-are-the-main-constituents-of-air-but","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n%e2%82%82-and-dioxygen-o%e2%82%82-are-the-main-constituents-of-air-but\/","title":{"rendered":"Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but"},"content":{"rendered":"<p>Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but they do not react with each other to form oxides of nitrogen because<\/p>\n<p>[amp_mcq option1=&#8221;the reaction requires initiation by a catalyst&#8221; option2=&#8221;oxides of nitrogen are unstable&#8221; option3=&#8221;the reaction is endothermic and requires very high temperature&#8221; option4=&#8221;the stoichiometry of N\u2082 and O\u2082 in air is not ideal for the reaction to take place&#8221; correct=&#8221;option3&#8243;]<\/p>\n<div class=\"psc-box-pyq-exam-year-detail\">\n<div class=\"pyq-exam\">\n<div class=\"psc-heading\">This question was previously asked in<\/div>\n<div class=\"psc-title line-ellipsis\">UPSC NDA-1 &#8211; 2019<\/div>\n<\/div>\n<div class=\"pyq-exam-psc-buttons\"><a href=\"\/pyq\/pyq-upsc-nda-1-2019.pdf\" target=\"_blank\" class=\"psc-pdf-button\" rel=\"noopener\">Download PDF<\/a><a href=\"\/pyq-upsc-nda-1-2019\" target=\"_blank\" class=\"psc-attempt-button\" rel=\"noopener\">Attempt Online<\/a><\/div>\n<\/div>\n<section id=\"pyq-correct-answer\">\nDinitrogen (N\u2082) and dioxygen (O\u2082) molecules are very stable due to strong bonds (triple bond in N\u2082, double bond in O\u2082). The reaction between them to form oxides of nitrogen, such as nitric oxide (NO), is highly endothermic (requires energy input) and has a high activation energy barrier. Therefore, this reaction requires very high temperatures (e.g., found in lightning strikes or internal combustion engines) to proceed significantly. At normal atmospheric temperatures, there isn&#8217;t enough energy to break the strong N\u2261N bond and initiate the reaction.<br \/>\n<\/section>\n<section id=\"pyq-key-points\">\n&#8211; The reaction N\u2082 + O\u2082 \u2192 2NO is endothermic (\u0394H > 0).<br \/>\n&#8211; The strong triple bond in N\u2082 requires a large amount of energy to break.<br \/>\n&#8211; Standard atmospheric temperatures are insufficient to overcome the activation energy barrier for this reaction.<br \/>\n<\/section>\n<section id=\"pyq-additional-information\">\nWhile a catalyst could potentially lower the activation energy, the primary reason the reaction doesn&#8217;t occur spontaneously in the air is the high energy requirement. Oxides of nitrogen, once formed, vary in stability, but their stability is not the reason for their lack of formation under normal conditions. The stoichiometry in air is about 4:1 N\u2082:O\u2082, which is not ideal for NO formation (1:1), but this ratio doesn&#8217;t prevent the reaction from occurring at all; it just affects equilibrium yield.<br \/>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but they do not react with each other to form oxides of nitrogen because [amp_mcq option1=&#8221;the reaction requires initiation by a catalyst&#8221; option2=&#8221;oxides of nitrogen are unstable&#8221; option3=&#8221;the reaction is endothermic and requires very high temperature&#8221; option4=&#8221;the stoichiometry of N\u2082 and O\u2082 in air &#8230; <\/p>\n<p class=\"read-more-container\"><a title=\"Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but\" class=\"read-more button\" href=\"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n%e2%82%82-and-dioxygen-o%e2%82%82-are-the-main-constituents-of-air-but\/#more-87665\">Detailed Solution<span class=\"screen-reader-text\">Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1093],"tags":[1119,1096,1245],"class_list":["post-87665","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-1","tag-1119","tag-chemistry","tag-sulphur-nitrogen-halogen-inert-gases","no-featured-image-padding"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.2 (Yoast SEO v23.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but<\/title>\n<meta name=\"description\" content=\"Dinitrogen (N\u2082) and dioxygen (O\u2082) molecules are very stable due to strong bonds (triple bond in N\u2082, double bond in O\u2082). The reaction between them to form oxides of nitrogen, such as nitric oxide (NO), is highly endothermic (requires energy input) and has a high activation energy barrier. Therefore, this reaction requires very high temperatures (e.g., found in lightning strikes or internal combustion engines) to proceed significantly. At normal atmospheric temperatures, there isn&#039;t enough energy to break the strong N\u2261N bond and initiate the reaction. - The reaction N\u2082 + O\u2082 \u2192 2NO is endothermic (\u0394H &gt; 0). - The strong triple bond in N\u2082 requires a large amount of energy to break. - Standard atmospheric temperatures are insufficient to overcome the activation energy barrier for this reaction.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n\u2082-and-dioxygen-o\u2082-are-the-main-constituents-of-air-but\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but\" \/>\n<meta property=\"og:description\" content=\"Dinitrogen (N\u2082) and dioxygen (O\u2082) molecules are very stable due to strong bonds (triple bond in N\u2082, double bond in O\u2082). The reaction between them to form oxides of nitrogen, such as nitric oxide (NO), is highly endothermic (requires energy input) and has a high activation energy barrier. Therefore, this reaction requires very high temperatures (e.g., found in lightning strikes or internal combustion engines) to proceed significantly. At normal atmospheric temperatures, there isn&#039;t enough energy to break the strong N\u2261N bond and initiate the reaction. - The reaction N\u2082 + O\u2082 \u2192 2NO is endothermic (\u0394H &gt; 0). - The strong triple bond in N\u2082 requires a large amount of energy to break. - Standard atmospheric temperatures are insufficient to overcome the activation energy barrier for this reaction.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n\u2082-and-dioxygen-o\u2082-are-the-main-constituents-of-air-but\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T06:50:50+00:00\" \/>\n<meta name=\"author\" content=\"rawan239\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"rawan239\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but","description":"Dinitrogen (N\u2082) and dioxygen (O\u2082) molecules are very stable due to strong bonds (triple bond in N\u2082, double bond in O\u2082). The reaction between them to form oxides of nitrogen, such as nitric oxide (NO), is highly endothermic (requires energy input) and has a high activation energy barrier. Therefore, this reaction requires very high temperatures (e.g., found in lightning strikes or internal combustion engines) to proceed significantly. At normal atmospheric temperatures, there isn't enough energy to break the strong N\u2261N bond and initiate the reaction. - The reaction N\u2082 + O\u2082 \u2192 2NO is endothermic (\u0394H > 0). - The strong triple bond in N\u2082 requires a large amount of energy to break. - Standard atmospheric temperatures are insufficient to overcome the activation energy barrier for this reaction.","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n\u2082-and-dioxygen-o\u2082-are-the-main-constituents-of-air-but\/","og_locale":"en_US","og_type":"article","og_title":"Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but","og_description":"Dinitrogen (N\u2082) and dioxygen (O\u2082) molecules are very stable due to strong bonds (triple bond in N\u2082, double bond in O\u2082). The reaction between them to form oxides of nitrogen, such as nitric oxide (NO), is highly endothermic (requires energy input) and has a high activation energy barrier. Therefore, this reaction requires very high temperatures (e.g., found in lightning strikes or internal combustion engines) to proceed significantly. At normal atmospheric temperatures, there isn't enough energy to break the strong N\u2261N bond and initiate the reaction. - The reaction N\u2082 + O\u2082 \u2192 2NO is endothermic (\u0394H > 0). - The strong triple bond in N\u2082 requires a large amount of energy to break. - Standard atmospheric temperatures are insufficient to overcome the activation energy barrier for this reaction.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n\u2082-and-dioxygen-o\u2082-are-the-main-constituents-of-air-but\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T06:50:50+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n%e2%82%82-and-dioxygen-o%e2%82%82-are-the-main-constituents-of-air-but\/","url":"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n%e2%82%82-and-dioxygen-o%e2%82%82-are-the-main-constituents-of-air-but\/","name":"Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T06:50:50+00:00","dateModified":"2025-06-01T06:50:50+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"Dinitrogen (N\u2082) and dioxygen (O\u2082) molecules are very stable due to strong bonds (triple bond in N\u2082, double bond in O\u2082). The reaction between them to form oxides of nitrogen, such as nitric oxide (NO), is highly endothermic (requires energy input) and has a high activation energy barrier. Therefore, this reaction requires very high temperatures (e.g., found in lightning strikes or internal combustion engines) to proceed significantly. At normal atmospheric temperatures, there isn't enough energy to break the strong N\u2261N bond and initiate the reaction. - The reaction N\u2082 + O\u2082 \u2192 2NO is endothermic (\u0394H > 0). - The strong triple bond in N\u2082 requires a large amount of energy to break. - Standard atmospheric temperatures are insufficient to overcome the activation energy barrier for this reaction.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n%e2%82%82-and-dioxygen-o%e2%82%82-are-the-main-constituents-of-air-but\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n%e2%82%82-and-dioxygen-o%e2%82%82-are-the-main-constituents-of-air-but\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/dinitrogen-n%e2%82%82-and-dioxygen-o%e2%82%82-are-the-main-constituents-of-air-but\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC NDA-1","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-nda-1\/"},{"@type":"ListItem","position":3,"name":"Dinitrogen (N\u2082) and dioxygen (O\u2082) are the main constituents of air but"}]},{"@type":"WebSite","@id":"https:\/\/exam.pscnotes.com\/mcq\/#website","url":"https:\/\/exam.pscnotes.com\/mcq\/","name":"MCQ and Quiz for Exams","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/exam.pscnotes.com\/mcq\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209","name":"rawan239","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/image\/","url":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/761a7274f9cce048fa5b921221e7934820d74514df93ef195a9d22af0c1c9001?s=96&d=mm&r=g","caption":"rawan239"},"sameAs":["https:\/\/exam.pscnotes.com"],"url":"https:\/\/exam.pscnotes.com\/mcq\/author\/rawan239\/"}]}},"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/87665","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/comments?post=87665"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/87665\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=87665"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=87665"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=87665"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}