{"id":88244,"date":"2025-06-01T07:06:18","date_gmt":"2025-06-01T07:06:18","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=88244"},"modified":"2025-06-01T07:06:18","modified_gmt":"2025-06-01T07:06:18","slug":"which-one-of-the-following-has-different-number-of-molecules-all-ar","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-has-different-number-of-molecules-all-ar\/","title":{"rendered":"Which one of the following has different number of molecules ? (All ar"},"content":{"rendered":"

Which one of the following has different number of molecules ? (All are kept at normal temperature and pressure)<\/p>\n

[amp_mcq option1=”3 gram of Hydrogen” option2=”48 gram of Oxygen” option3=”42 gram of Nitrogen” option4=”2 gram of Carbon” correct=”option4″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC NDA-2 – 2016<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nTo determine which option has a different number of molecules, we need to calculate the number of moles for each substance. The number of molecules is directly proportional to the number of moles (Avogadro’s law states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules; here we are comparing masses).
\n– A) 3 gram of Hydrogen (H\u2082): Molar mass \u2248 2 g\/mol. Moles = 3 g \/ 2 g\/mol = 1.5 moles.
\n– B) 48 gram of Oxygen (O\u2082): Molar mass \u2248 32 g\/mol. Moles = 48 g \/ 32 g\/mol = 1.5 moles.
\n– C) 42 gram of Nitrogen (N\u2082): Molar mass \u2248 28 g\/mol. Moles = 42 g \/ 28 g\/mol = 1.5 moles.
\n– D) 2 gram of Carbon (C): Molar mass \u2248 12 g\/mol. Moles = 2 g \/ 12 g\/mol = 1\/6 moles \u2248 0.167 moles.
\nOptions A, B, and C all contain 1.5 moles (and thus the same number of molecules). Option D contains a significantly different number of moles (and thus atoms, as carbon exists as atoms in its elemental solid form).
\n<\/section>\n
\n– The number of molecules in a given mass of a substance is proportional to the number of moles, which is calculated as Mass \/ Molar Mass.
\n– Avogadro’s number (approximately 6.022 x 10\u00b2\u00b3) represents the number of particles (atoms, molecules, etc.) in one mole of a substance.
\n<\/section>\n
\nThe condition “All are kept at normal temperature and pressure” (NTP) is relevant for comparing volumes of gases using Avogadro’s law, but here we are comparing masses and thus the number of moles\/molecules directly using molar masses. Note that elemental carbon is a solid at NTP, while hydrogen, oxygen, and nitrogen are gases (diatomic molecules H\u2082, O\u2082, N\u2082). The question phrasing “number of molecules” for carbon is slightly imprecise as solid carbon consists of atoms in a lattice, but the underlying principle is comparing the amount of substance (moles).
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Which one of the following has different number of molecules ? (All are kept at normal temperature and pressure) [amp_mcq option1=”3 gram of Hydrogen” option2=”48 gram of Oxygen” option3=”42 gram of Nitrogen” option4=”2 gram of Carbon” correct=”option4″] This question was previously asked in UPSC NDA-2 – 2016 Download PDFAttempt Online To determine which option has … <\/p>\n

Detailed SolutionWhich one of the following has different number of molecules ? (All ar<\/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":[1094],"tags":[1098,1096,1239],"class_list":["post-88244","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-2","tag-1098","tag-chemistry","tag-inorganic-chemistry","no-featured-image-padding"],"yoast_head":"\nWhich one of the following has different number of molecules ? (All ar<\/title>\n<meta name=\"description\" content=\"To determine which option has a different number of molecules, we need to calculate the number of moles for each substance. The number of molecules is directly proportional to the number of moles (Avogadro's law states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules; here we are comparing masses). - A) 3 gram of Hydrogen (H\u2082): Molar mass \u2248 2 g\/mol. Moles = 3 g \/ 2 g\/mol = 1.5 moles. - B) 48 gram of Oxygen (O\u2082): Molar mass \u2248 32 g\/mol. Moles = 48 g \/ 32 g\/mol = 1.5 moles. - C) 42 gram of Nitrogen (N\u2082): Molar mass \u2248 28 g\/mol. Moles = 42 g \/ 28 g\/mol = 1.5 moles. - D) 2 gram of Carbon (C): Molar mass \u2248 12 g\/mol. Moles = 2 g \/ 12 g\/mol = 1\/6 moles \u2248 0.167 moles. Options A, B, and C all contain 1.5 moles (and thus the same number of molecules). Option D contains a significantly different number of moles (and thus atoms, as carbon exists as atoms in its elemental solid form). - The number of molecules in a given mass of a substance is proportional to the number of moles, which is calculated as Mass \/ Molar Mass. - Avogadro's number (approximately 6.022 x 10\u00b2\u00b3) represents the number of particles (atoms, molecules, etc.) in one mole of a substance.\" \/>\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-has-different-number-of-molecules-all-ar\/\" \/>\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 has different number of molecules ? (All ar\" \/>\n<meta property=\"og:description\" content=\"To determine which option has a different number of molecules, we need to calculate the number of moles for each substance. The number of molecules is directly proportional to the number of moles (Avogadro's law states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules; here we are comparing masses). - A) 3 gram of Hydrogen (H\u2082): Molar mass \u2248 2 g\/mol. Moles = 3 g \/ 2 g\/mol = 1.5 moles. - B) 48 gram of Oxygen (O\u2082): Molar mass \u2248 32 g\/mol. Moles = 48 g \/ 32 g\/mol = 1.5 moles. - C) 42 gram of Nitrogen (N\u2082): Molar mass \u2248 28 g\/mol. Moles = 42 g \/ 28 g\/mol = 1.5 moles. - D) 2 gram of Carbon (C): Molar mass \u2248 12 g\/mol. Moles = 2 g \/ 12 g\/mol = 1\/6 moles \u2248 0.167 moles. Options A, B, and C all contain 1.5 moles (and thus the same number of molecules). Option D contains a significantly different number of moles (and thus atoms, as carbon exists as atoms in its elemental solid form). - The number of molecules in a given mass of a substance is proportional to the number of moles, which is calculated as Mass \/ Molar Mass. - Avogadro's number (approximately 6.022 x 10\u00b2\u00b3) represents the number of particles (atoms, molecules, etc.) in one mole of a substance.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-has-different-number-of-molecules-all-ar\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T07:06:18+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=\"2 minutes\" \/>\n<!-- \/ Yoast SEO Premium plugin. -->","yoast_head_json":{"title":"Which one of the following has different number of molecules ? (All ar","description":"To determine which option has a different number of molecules, we need to calculate the number of moles for each substance. The number of molecules is directly proportional to the number of moles (Avogadro's law states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules; here we are comparing masses). - A) 3 gram of Hydrogen (H\u2082): Molar mass \u2248 2 g\/mol. Moles = 3 g \/ 2 g\/mol = 1.5 moles. - B) 48 gram of Oxygen (O\u2082): Molar mass \u2248 32 g\/mol. Moles = 48 g \/ 32 g\/mol = 1.5 moles. - C) 42 gram of Nitrogen (N\u2082): Molar mass \u2248 28 g\/mol. Moles = 42 g \/ 28 g\/mol = 1.5 moles. - D) 2 gram of Carbon (C): Molar mass \u2248 12 g\/mol. Moles = 2 g \/ 12 g\/mol = 1\/6 moles \u2248 0.167 moles. Options A, B, and C all contain 1.5 moles (and thus the same number of molecules). Option D contains a significantly different number of moles (and thus atoms, as carbon exists as atoms in its elemental solid form). - The number of molecules in a given mass of a substance is proportional to the number of moles, which is calculated as Mass \/ Molar Mass. - Avogadro's number (approximately 6.022 x 10\u00b2\u00b3) represents the number of particles (atoms, molecules, etc.) in one mole of a substance.","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\/which-one-of-the-following-has-different-number-of-molecules-all-ar\/","og_locale":"en_US","og_type":"article","og_title":"Which one of the following has different number of molecules ? (All ar","og_description":"To determine which option has a different number of molecules, we need to calculate the number of moles for each substance. The number of molecules is directly proportional to the number of moles (Avogadro's law states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules; here we are comparing masses). - A) 3 gram of Hydrogen (H\u2082): Molar mass \u2248 2 g\/mol. Moles = 3 g \/ 2 g\/mol = 1.5 moles. - B) 48 gram of Oxygen (O\u2082): Molar mass \u2248 32 g\/mol. Moles = 48 g \/ 32 g\/mol = 1.5 moles. - C) 42 gram of Nitrogen (N\u2082): Molar mass \u2248 28 g\/mol. Moles = 42 g \/ 28 g\/mol = 1.5 moles. - D) 2 gram of Carbon (C): Molar mass \u2248 12 g\/mol. Moles = 2 g \/ 12 g\/mol = 1\/6 moles \u2248 0.167 moles. Options A, B, and C all contain 1.5 moles (and thus the same number of molecules). Option D contains a significantly different number of moles (and thus atoms, as carbon exists as atoms in its elemental solid form). - The number of molecules in a given mass of a substance is proportional to the number of moles, which is calculated as Mass \/ Molar Mass. - Avogadro's number (approximately 6.022 x 10\u00b2\u00b3) represents the number of particles (atoms, molecules, etc.) in one mole of a substance.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-has-different-number-of-molecules-all-ar\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T07:06:18+00:00","author":"rawan239","twitter_card":"summary_large_image","twitter_misc":{"Written by":"rawan239","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-has-different-number-of-molecules-all-ar\/","url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-has-different-number-of-molecules-all-ar\/","name":"Which one of the following has different number of molecules ? (All ar","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T07:06:18+00:00","dateModified":"2025-06-01T07:06:18+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"To determine which option has a different number of molecules, we need to calculate the number of moles for each substance. The number of molecules is directly proportional to the number of moles (Avogadro's law states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules; here we are comparing masses). - A) 3 gram of Hydrogen (H\u2082): Molar mass \u2248 2 g\/mol. Moles = 3 g \/ 2 g\/mol = 1.5 moles. - B) 48 gram of Oxygen (O\u2082): Molar mass \u2248 32 g\/mol. Moles = 48 g \/ 32 g\/mol = 1.5 moles. - C) 42 gram of Nitrogen (N\u2082): Molar mass \u2248 28 g\/mol. Moles = 42 g \/ 28 g\/mol = 1.5 moles. - D) 2 gram of Carbon (C): Molar mass \u2248 12 g\/mol. Moles = 2 g \/ 12 g\/mol = 1\/6 moles \u2248 0.167 moles. Options A, B, and C all contain 1.5 moles (and thus the same number of molecules). Option D contains a significantly different number of moles (and thus atoms, as carbon exists as atoms in its elemental solid form). - The number of molecules in a given mass of a substance is proportional to the number of moles, which is calculated as Mass \/ Molar Mass. - Avogadro's number (approximately 6.022 x 10\u00b2\u00b3) represents the number of particles (atoms, molecules, etc.) in one mole of a substance.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-has-different-number-of-molecules-all-ar\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-has-different-number-of-molecules-all-ar\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-has-different-number-of-molecules-all-ar\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC NDA-2","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-nda-2\/"},{"@type":"ListItem","position":3,"name":"Which one of the following has different number of molecules ? 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