{"id":87241,"date":"2025-06-01T06:38:22","date_gmt":"2025-06-01T06:38:22","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=87241"},"modified":"2025-06-01T06:38:22","modified_gmt":"2025-06-01T06:38:22","slug":"statement-i-colour-of-nitrogen-dioxide-changes-to-colourless-at-low-t","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/statement-i-colour-of-nitrogen-dioxide-changes-to-colourless-at-low-t\/","title":{"rendered":"Statement-I: Colour of nitrogen dioxide changes to colourless at low t"},"content":{"rendered":"

Statement-I: Colour of nitrogen dioxide changes to colourless at low temperature.
\nStatement-II: At low temperature Nitrogen tetroxide (N\u2082O\u2084) is formed which is colourless.<\/p>\n

[amp_mcq option1=”Both the statements are individually true and Statement II is the correct explanation of Statement I” option2=”Both the statements are individually true but Statement II is not the correct explanation of Statement I” option3=”Statement I is true but Statement II is false” option4=”Statement I is false but Statement II is true” correct=”option1″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC NDA-1 – 2015<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nBoth Statement I and Statement II are individually true, and Statement II is the correct explanation of Statement I.
\n<\/section>\n
\nStatement I is true; the reddish-brown colour of nitrogen dioxide gas disappears at low temperatures. Statement II is also true; at low temperatures, nitrogen dioxide dimerizes to form colourless nitrogen tetroxide (N\u2082O\u2084).
\n<\/section>\n
\nNitrogen dioxide (NO\u2082) is an equilibrium mixture with its dimer, dinitrogen tetroxide (N\u2082O\u2084):
\n2NO\u2082(g) (reddish-brown) \u21cc N\u2082O\u2084(g) (colourless)
\nThis dimerization reaction is exothermic (\u0394H < 0). According to Le Chatelier's principle, decreasing the temperature shifts the equilibrium towards the exothermic reaction, favoring the formation of N\u2082O\u2084. As the temperature decreases, more NO\u2082 dimerizes into colourless N\u2082O\u2084, causing the colour of the gas mixture to fade to colourless. Statement II correctly identifies the formation of colourless N\u2082O\u2084 as the reason for the colour change.\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Statement-I: Colour of nitrogen dioxide changes to colourless at low temperature. Statement-II: At low temperature Nitrogen tetroxide (N\u2082O\u2084) is formed which is colourless. [amp_mcq option1=”Both the statements are individually true and Statement II is the correct explanation of Statement I” option2=”Both the statements are individually true but Statement II is not the correct explanation of … <\/p>\n

Detailed SolutionStatement-I: Colour of nitrogen dioxide changes to colourless at low t<\/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":[1443,1096,1245],"class_list":["post-87241","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-1","tag-1443","tag-chemistry","tag-sulphur-nitrogen-halogen-inert-gases","no-featured-image-padding"],"yoast_head":"\nStatement-I: Colour of nitrogen dioxide changes to colourless at low t<\/title>\n<meta name=\"description\" content=\"Both Statement I and Statement II are individually true, and Statement II is the correct explanation of Statement I. Statement I is true; the reddish-brown colour of nitrogen dioxide gas disappears at low temperatures. Statement II is also true; at low temperatures, nitrogen dioxide dimerizes to form colourless nitrogen tetroxide (N\u2082O\u2084).\" \/>\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\/statement-i-colour-of-nitrogen-dioxide-changes-to-colourless-at-low-t\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Statement-I: Colour of nitrogen dioxide changes to colourless at low t\" \/>\n<meta property=\"og:description\" content=\"Both Statement I and Statement II are individually true, and Statement II is the correct explanation of Statement I. Statement I is true; the reddish-brown colour of nitrogen dioxide gas disappears at low temperatures. 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