{"id":85384,"date":"2025-06-01T03:15:05","date_gmt":"2025-06-01T03:15:05","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=85384"},"modified":"2025-06-01T03:15:05","modified_gmt":"2025-06-01T03:15:05","slug":"naphthalene-burns-with-a-yellow-sooty-flame-this-is-because","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/","title":{"rendered":"Naphthalene burns with a yellow sooty flame. This is because"},"content":{"rendered":"

Naphthalene burns with a yellow sooty flame. This is because<\/p>\n

[amp_mcq option1=”carbon to hydrogen ratio is low” option2=”there is incomplete combustion” option3=”there is excess supply of air” option4=”of presence of impurities of nitrogen and sulfur” correct=”option2″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CDS-1 – 2023<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nWhen a substance burns with a yellow, sooty flame, it indicates that combustion is incomplete. Combustion is a chemical process where a substance reacts rapidly with oxygen to produce heat and light. Complete combustion occurs when there is sufficient oxygen, producing primarily carbon dioxide and water. Incomplete combustion occurs when there is insufficient oxygen, leading to the formation of carbon monoxide and\/or unburnt carbon particles (soot). The yellow colour of the flame is due to the incandescence (glowing due to heat) of these hot soot particles. Naphthalene (C\u2081\u2080H\u2088) is an aromatic hydrocarbon with a relatively high carbon-to-hydrogen ratio compared to simple alkanes. Compounds with higher carbon content require more oxygen for complete combustion and are more prone to incomplete combustion and soot formation, especially in open air where the oxygen supply may not be perfectly mixed.
\n<\/section>\n
\n– A yellow sooty flame is a characteristic sign of incomplete combustion.
\n– Incomplete combustion produces soot (unburnt carbon particles) which glow yellow when hot.
\n– Fuels with a high carbon-to-hydrogen ratio are more likely to produce sooty flames during incomplete combustion.
\n<\/section>\n
\nIn contrast, complete combustion typically produces a clean, often blue, flame (as seen in a Bunsen burner with the air hole open or a gas stove flame). Factors affecting the completeness of combustion include the amount of oxygen available, the mixing of fuel and air, and the temperature.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Naphthalene burns with a yellow sooty flame. This is because [amp_mcq option1=”carbon to hydrogen ratio is low” option2=”there is incomplete combustion” option3=”there is excess supply of air” option4=”of presence of impurities of nitrogen and sulfur” correct=”option2″] This question was previously asked in UPSC CDS-1 – 2023 Download PDFAttempt Online When a substance burns with a … <\/p>\n

Detailed SolutionNaphthalene burns with a yellow sooty flame. This is because<\/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":[1087],"tags":[1105,1096,1330],"class_list":["post-85384","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1105","tag-chemistry","tag-hydrocarbons","no-featured-image-padding"],"yoast_head":"\nNaphthalene burns with a yellow sooty flame. This is because<\/title>\n<meta name=\"description\" content=\"When a substance burns with a yellow, sooty flame, it indicates that combustion is incomplete. Combustion is a chemical process where a substance reacts rapidly with oxygen to produce heat and light. Complete combustion occurs when there is sufficient oxygen, producing primarily carbon dioxide and water. Incomplete combustion occurs when there is insufficient oxygen, leading to the formation of carbon monoxide and\/or unburnt carbon particles (soot). The yellow colour of the flame is due to the incandescence (glowing due to heat) of these hot soot particles. Naphthalene (C\u2081\u2080H\u2088) is an aromatic hydrocarbon with a relatively high carbon-to-hydrogen ratio compared to simple alkanes. Compounds with higher carbon content require more oxygen for complete combustion and are more prone to incomplete combustion and soot formation, especially in open air where the oxygen supply may not be perfectly mixed. - A yellow sooty flame is a characteristic sign of incomplete combustion. - Incomplete combustion produces soot (unburnt carbon particles) which glow yellow when hot. - Fuels with a high carbon-to-hydrogen ratio are more likely to produce sooty flames during incomplete combustion.\" \/>\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\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Naphthalene burns with a yellow sooty flame. This is because\" \/>\n<meta property=\"og:description\" content=\"When a substance burns with a yellow, sooty flame, it indicates that combustion is incomplete. Combustion is a chemical process where a substance reacts rapidly with oxygen to produce heat and light. Complete combustion occurs when there is sufficient oxygen, producing primarily carbon dioxide and water. Incomplete combustion occurs when there is insufficient oxygen, leading to the formation of carbon monoxide and\/or unburnt carbon particles (soot). The yellow colour of the flame is due to the incandescence (glowing due to heat) of these hot soot particles. Naphthalene (C\u2081\u2080H\u2088) is an aromatic hydrocarbon with a relatively high carbon-to-hydrogen ratio compared to simple alkanes. Compounds with higher carbon content require more oxygen for complete combustion and are more prone to incomplete combustion and soot formation, especially in open air where the oxygen supply may not be perfectly mixed. - A yellow sooty flame is a characteristic sign of incomplete combustion. - Incomplete combustion produces soot (unburnt carbon particles) which glow yellow when hot. - Fuels with a high carbon-to-hydrogen ratio are more likely to produce sooty flames during incomplete combustion.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T03:15:05+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":"Naphthalene burns with a yellow sooty flame. This is because","description":"When a substance burns with a yellow, sooty flame, it indicates that combustion is incomplete. Combustion is a chemical process where a substance reacts rapidly with oxygen to produce heat and light. Complete combustion occurs when there is sufficient oxygen, producing primarily carbon dioxide and water. Incomplete combustion occurs when there is insufficient oxygen, leading to the formation of carbon monoxide and\/or unburnt carbon particles (soot). The yellow colour of the flame is due to the incandescence (glowing due to heat) of these hot soot particles. Naphthalene (C\u2081\u2080H\u2088) is an aromatic hydrocarbon with a relatively high carbon-to-hydrogen ratio compared to simple alkanes. Compounds with higher carbon content require more oxygen for complete combustion and are more prone to incomplete combustion and soot formation, especially in open air where the oxygen supply may not be perfectly mixed. - A yellow sooty flame is a characteristic sign of incomplete combustion. - Incomplete combustion produces soot (unburnt carbon particles) which glow yellow when hot. - Fuels with a high carbon-to-hydrogen ratio are more likely to produce sooty flames during incomplete combustion.","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\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/","og_locale":"en_US","og_type":"article","og_title":"Naphthalene burns with a yellow sooty flame. This is because","og_description":"When a substance burns with a yellow, sooty flame, it indicates that combustion is incomplete. Combustion is a chemical process where a substance reacts rapidly with oxygen to produce heat and light. Complete combustion occurs when there is sufficient oxygen, producing primarily carbon dioxide and water. Incomplete combustion occurs when there is insufficient oxygen, leading to the formation of carbon monoxide and\/or unburnt carbon particles (soot). The yellow colour of the flame is due to the incandescence (glowing due to heat) of these hot soot particles. Naphthalene (C\u2081\u2080H\u2088) is an aromatic hydrocarbon with a relatively high carbon-to-hydrogen ratio compared to simple alkanes. Compounds with higher carbon content require more oxygen for complete combustion and are more prone to incomplete combustion and soot formation, especially in open air where the oxygen supply may not be perfectly mixed. - A yellow sooty flame is a characteristic sign of incomplete combustion. - Incomplete combustion produces soot (unburnt carbon particles) which glow yellow when hot. - Fuels with a high carbon-to-hydrogen ratio are more likely to produce sooty flames during incomplete combustion.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T03:15:05+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\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/","url":"https:\/\/exam.pscnotes.com\/mcq\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/","name":"Naphthalene burns with a yellow sooty flame. This is because","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T03:15:05+00:00","dateModified":"2025-06-01T03:15:05+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"When a substance burns with a yellow, sooty flame, it indicates that combustion is incomplete. Combustion is a chemical process where a substance reacts rapidly with oxygen to produce heat and light. Complete combustion occurs when there is sufficient oxygen, producing primarily carbon dioxide and water. Incomplete combustion occurs when there is insufficient oxygen, leading to the formation of carbon monoxide and\/or unburnt carbon particles (soot). The yellow colour of the flame is due to the incandescence (glowing due to heat) of these hot soot particles. Naphthalene (C\u2081\u2080H\u2088) is an aromatic hydrocarbon with a relatively high carbon-to-hydrogen ratio compared to simple alkanes. Compounds with higher carbon content require more oxygen for complete combustion and are more prone to incomplete combustion and soot formation, especially in open air where the oxygen supply may not be perfectly mixed. - A yellow sooty flame is a characteristic sign of incomplete combustion. - Incomplete combustion produces soot (unburnt carbon particles) which glow yellow when hot. - Fuels with a high carbon-to-hydrogen ratio are more likely to produce sooty flames during incomplete combustion.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/naphthalene-burns-with-a-yellow-sooty-flame-this-is-because\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC CDS-1","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-cds-1\/"},{"@type":"ListItem","position":3,"name":"Naphthalene burns with a yellow sooty flame. This is because"}]},{"@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\/85384","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=85384"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/85384\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=85384"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=85384"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=85384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}