{"id":86406,"date":"2025-06-01T03:46:17","date_gmt":"2025-06-01T03:46:17","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=86406"},"modified":"2025-06-01T03:46:17","modified_gmt":"2025-06-01T03:46:17","slug":"during-white-washing-of-walls-slaked-lime-reacts-slowly-with-carbon-d","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/during-white-washing-of-walls-slaked-lime-reacts-slowly-with-carbon-d\/","title":{"rendered":"During white-washing of walls, slaked lime reacts slowly with carbon d"},"content":{"rendered":"

During white-washing of walls, slaked lime reacts slowly with carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Which of the following reactions represents this correctly ?<\/p>\n

[amp_mcq option1=”$\\text{CaO (s) + CO}_2\\text{ (g)} \\rightarrow \\text{CaCO}_3\\text{ (s)}$” option2=”$\\text{CaO (l) + CO}_2\\text{ (g)} \\rightarrow \\text{CaCO}_3\\text{ (s)}$” option3=”$\\text{Ca(OH)}_2\\text{ (l) + CO}_2\\text{ (l)} \\rightarrow \\text{CaCO}_3\\text{ (s)} + \\text{H}_2\\text{O (l)}$” option4=”$\\text{Ca(OH)}_2\\text{ (aq) + CO}_2\\text{ (g)} \\rightarrow \\text{CaCO}_3\\text{ (s)} + \\text{H}_2\\text{O (l)}$” correct=”option4″]<\/p>\n

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This question was previously asked in<\/div>\n
UPSC CDS-2 – 2023<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nWhite-washing uses slaked lime, which is calcium hydroxide (Ca(OH)2), typically applied as an aqueous suspension or solution. This slaked lime reacts slowly with carbon dioxide (CO2) from the air to form calcium carbonate (CaCO3), a hard, white substance that coats the wall. Water is also produced in this reaction. The correct chemical equation representing this process is Ca(OH)2 (aq) + CO2 (g) $\\rightarrow$ CaCO3 (s) + H2O (l).
\n<\/section>\n
\nSlaked lime (Ca(OH)2) is produced by adding water to quicklime (CaO). The reaction of slaked lime with atmospheric CO2 is a slow carbonation process that hardens the white-washed surface. The state symbols are important: slaked lime is in aqueous form (aq), CO2 is a gas (g), calcium carbonate formed is a solid (s), and water is a liquid (l).
\n<\/section>\n
\nOption A and B use CaO (quicklime) instead of Ca(OH)2 (slaked lime). Option C uses incorrect state symbols for both Ca(OH)2 (l instead of aq) and CO2 (l instead of g). Option D correctly shows the reactants, products, stoichiometry, and state symbols for the reaction described.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

During white-washing of walls, slaked lime reacts slowly with carbon dioxide in air to form a thin layer of calcium carbonate on the walls. Which of the following reactions represents this correctly ? [amp_mcq option1=”$\\text{CaO (s) + CO}_2\\text{ (g)} \\rightarrow \\text{CaCO}_3\\text{ (s)}$” option2=”$\\text{CaO (l) + CO}_2\\text{ (g)} \\rightarrow \\text{CaCO}_3\\text{ (s)}$” option3=”$\\text{Ca(OH)}_2\\text{ (l) + CO}_2\\text{ (l)} … <\/p>\n

Detailed SolutionDuring white-washing of walls, slaked lime reacts slowly with carbon d<\/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":[1088],"tags":[1105,1202,1096],"class_list":["post-86406","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-2","tag-1105","tag-acid-base-and-salt","tag-chemistry","no-featured-image-padding"],"yoast_head":"\nDuring white-washing of walls, slaked lime reacts slowly with carbon d<\/title>\n<meta name=\"description\" content=\"White-washing uses slaked lime, which is calcium hydroxide (Ca(OH)2), typically applied as an aqueous suspension or solution. This slaked lime reacts slowly with carbon dioxide (CO2) from the air to form calcium carbonate (CaCO3), a hard, white substance that coats the wall. Water is also produced in this reaction. The correct chemical equation representing this process is Ca(OH)2 (aq) + CO2 (g) $rightarrow$ CaCO3 (s) + H2O (l). Slaked lime (Ca(OH)2) is produced by adding water to quicklime (CaO). The reaction of slaked lime with atmospheric CO2 is a slow carbonation process that hardens the white-washed surface. The state symbols are important: slaked lime is in aqueous form (aq), CO2 is a gas (g), calcium carbonate formed is a solid (s), and water is a liquid (l).\" \/>\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\/during-white-washing-of-walls-slaked-lime-reacts-slowly-with-carbon-d\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"During white-washing of walls, slaked lime reacts slowly with carbon d\" \/>\n<meta property=\"og:description\" content=\"White-washing uses slaked lime, which is calcium hydroxide (Ca(OH)2), typically applied as an aqueous suspension or solution. This slaked lime reacts slowly with carbon dioxide (CO2) from the air to form calcium carbonate (CaCO3), a hard, white substance that coats the wall. Water is also produced in this reaction. The correct chemical equation representing this process is Ca(OH)2 (aq) + CO2 (g) $rightarrow$ CaCO3 (s) + H2O (l). Slaked lime (Ca(OH)2) is produced by adding water to quicklime (CaO). The reaction of slaked lime with atmospheric CO2 is a slow carbonation process that hardens the white-washed surface. The state symbols are important: slaked lime is in aqueous form (aq), CO2 is a gas (g), calcium carbonate formed is a solid (s), and water is a liquid (l).\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/during-white-washing-of-walls-slaked-lime-reacts-slowly-with-carbon-d\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T03:46:17+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":"During white-washing of walls, slaked lime reacts slowly with carbon d","description":"White-washing uses slaked lime, which is calcium hydroxide (Ca(OH)2), typically applied as an aqueous suspension or solution. This slaked lime reacts slowly with carbon dioxide (CO2) from the air to form calcium carbonate (CaCO3), a hard, white substance that coats the wall. Water is also produced in this reaction. The correct chemical equation representing this process is Ca(OH)2 (aq) + CO2 (g) $rightarrow$ CaCO3 (s) + H2O (l). Slaked lime (Ca(OH)2) is produced by adding water to quicklime (CaO). The reaction of slaked lime with atmospheric CO2 is a slow carbonation process that hardens the white-washed surface. The state symbols are important: slaked lime is in aqueous form (aq), CO2 is a gas (g), calcium carbonate formed is a solid (s), and water is a liquid (l).","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\/during-white-washing-of-walls-slaked-lime-reacts-slowly-with-carbon-d\/","og_locale":"en_US","og_type":"article","og_title":"During white-washing of walls, slaked lime reacts slowly with carbon d","og_description":"White-washing uses slaked lime, which is calcium hydroxide (Ca(OH)2), typically applied as an aqueous suspension or solution. This slaked lime reacts slowly with carbon dioxide (CO2) from the air to form calcium carbonate (CaCO3), a hard, white substance that coats the wall. Water is also produced in this reaction. The correct chemical equation representing this process is Ca(OH)2 (aq) + CO2 (g) $rightarrow$ CaCO3 (s) + H2O (l). Slaked lime (Ca(OH)2) is produced by adding water to quicklime (CaO). The reaction of slaked lime with atmospheric CO2 is a slow carbonation process that hardens the white-washed surface. The state symbols are important: slaked lime is in aqueous form (aq), CO2 is a gas (g), calcium carbonate formed is a solid (s), and water is a liquid (l).","og_url":"https:\/\/exam.pscnotes.com\/mcq\/during-white-washing-of-walls-slaked-lime-reacts-slowly-with-carbon-d\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T03:46:17+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\/during-white-washing-of-walls-slaked-lime-reacts-slowly-with-carbon-d\/","url":"https:\/\/exam.pscnotes.com\/mcq\/during-white-washing-of-walls-slaked-lime-reacts-slowly-with-carbon-d\/","name":"During white-washing of walls, slaked lime reacts slowly with carbon d","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T03:46:17+00:00","dateModified":"2025-06-01T03:46:17+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"White-washing uses slaked lime, which is calcium hydroxide (Ca(OH)2), typically applied as an aqueous suspension or solution. 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