{"id":86877,"date":"2025-06-01T04:22:29","date_gmt":"2025-06-01T04:22:29","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=86877"},"modified":"2025-06-01T04:22:29","modified_gmt":"2025-06-01T04:22:29","slug":"which-one-of-the-following-gases-is-the-lightest","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-gases-is-the-lightest\/","title":{"rendered":"Which one of the following gases is the lightest?"},"content":{"rendered":"

Which one of the following gases is the lightest?<\/p>\n

[amp_mcq option1=”Hydrogen” option2=”Helium” option3=”Oxygen” option4=”Nitrogen” correct=”option1″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC Geoscientist – 2022<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe lightness of a gas is determined by its molecular or atomic mass (for noble gases). Lighter gases have lower molecular\/atomic masses and, at the same temperature and pressure, lower densities. Comparing the molar masses:
\n– Hydrogen (H\u2082): approx. 2.016 g\/mol
\n– Helium (He): approx. 4.003 g\/mol
\n– Oxygen (O\u2082): approx. 32.00 g\/mol
\n– Nitrogen (N\u2082): approx. 28.01 g\/mol
\nHydrogen (H\u2082) has the lowest molar mass among the given options, making it the lightest gas.
\n<\/section>\n
\n– Gas density is directly proportional to its molar mass at constant temperature and pressure (Ideal Gas Law).
\n– Comparing molar masses allows identification of the lightest gas.
\n<\/section>\n
\nHydrogen is the most abundant chemical substance in the universe. It is a highly flammable diatomic gas (H\u2082) under standard conditions. Helium is the second lightest element and is a noble gas, existing as a single atom (He). Oxygen and Nitrogen are the main components of Earth’s atmosphere, existing as diatomic molecules (O\u2082 and N\u2082).
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Which one of the following gases is the lightest? [amp_mcq option1=”Hydrogen” option2=”Helium” option3=”Oxygen” option4=”Nitrogen” correct=”option1″] This question was previously asked in UPSC Geoscientist – 2022 Download PDFAttempt Online The lightness of a gas is determined by its molecular or atomic mass (for noble gases). Lighter gases have lower molecular\/atomic masses and, at the same temperature … <\/p>\n

Detailed SolutionWhich one of the following gases is the lightest?<\/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":[1091],"tags":[1108,1096,1115],"class_list":["post-86877","post","type-post","status-publish","format-standard","hentry","category-upsc-geoscientist","tag-1108","tag-chemistry","tag-miscellaneous","no-featured-image-padding"],"yoast_head":"\nWhich one of the following gases is the lightest?<\/title>\n<meta name=\"description\" content=\"The lightness of a gas is determined by its molecular or atomic mass (for noble gases). Lighter gases have lower molecular\/atomic masses and, at the same temperature and pressure, lower densities. Comparing the molar masses: - Hydrogen (H\u2082): approx. 2.016 g\/mol - Helium (He): approx. 4.003 g\/mol - Oxygen (O\u2082): approx. 32.00 g\/mol - Nitrogen (N\u2082): approx. 28.01 g\/mol Hydrogen (H\u2082) has the lowest molar mass among the given options, making it the lightest gas. - Gas density is directly proportional to its molar mass at constant temperature and pressure (Ideal Gas Law). - Comparing molar masses allows identification of the lightest gas.\" \/>\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\/which-one-of-the-following-gases-is-the-lightest\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Which one of the following gases is the lightest?\" \/>\n<meta property=\"og:description\" content=\"The lightness of a gas is determined by its molecular or atomic mass (for noble gases). Lighter gases have lower molecular\/atomic masses and, at the same temperature and pressure, lower densities. Comparing the molar masses: - Hydrogen (H\u2082): approx. 2.016 g\/mol - Helium (He): approx. 4.003 g\/mol - Oxygen (O\u2082): approx. 32.00 g\/mol - Nitrogen (N\u2082): approx. 28.01 g\/mol Hydrogen (H\u2082) has the lowest molar mass among the given options, making it the lightest gas. - Gas density is directly proportional to its molar mass at constant temperature and pressure (Ideal Gas Law). - Comparing molar masses allows identification of the lightest gas.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-gases-is-the-lightest\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T04:22:29+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":"Which one of the following gases is the lightest?","description":"The lightness of a gas is determined by its molecular or atomic mass (for noble gases). 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