{"id":85343,"date":"2025-06-01T03:12:44","date_gmt":"2025-06-01T03:12:44","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=85343"},"modified":"2025-06-01T03:12:44","modified_gmt":"2025-06-01T03:12:44","slug":"which-of-the-following-statements-with-regard-to-the-reaction-given-be","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-of-the-following-statements-with-regard-to-the-reaction-given-be\/","title":{"rendered":"Which of the following statements with regard to the reaction given be"},"content":{"rendered":"<p>Which of the following statements with regard to the reaction given below are correct? CaO(s) + H\u2082O(l) \u2192 Ca(OH)\u2082(aq) + Heat<\/p>\n<ul>\n<li>1. Quicklime is used for white-washing of walls.<\/li>\n<li>2. The solution of slaked lime is used for whitewashing of walls.<\/li>\n<li>3. CaO reacts slowly with CO\u2082 in air to form a thin layer of CaCO\u2083 on walls.<\/li>\n<li>4. Calcium hydroxide called \u2018slaked lime\u2019 is an inorganic compound.<\/li>\n<\/ul>\n<p>Select the correct answer using the code given below.<\/p>\n<p>[amp_mcq option1=&#8221;1 and 4 only&#8221; option2=&#8221;2 and 4&#8243; option3=&#8221;2 and 3&#8243; option4=&#8221;1, 3 and 4&#8243; correct=&#8221;option2&#8243;]<\/p>\n<div class=\"psc-box-pyq-exam-year-detail\">\n<div class=\"pyq-exam\">\n<div class=\"psc-heading\">This question was previously asked in<\/div>\n<div class=\"psc-title line-ellipsis\">UPSC CDS-1 &#8211; 2023<\/div>\n<\/div>\n<div class=\"pyq-exam-psc-buttons\"><a href=\"\/pyq\/pyq-upsc-cds-1-2023.pdf\" target=\"_blank\" class=\"psc-pdf-button\" rel=\"noopener\">Download PDF<\/a><a href=\"\/pyq-upsc-cds-1-2023\" target=\"_blank\" class=\"psc-attempt-button\" rel=\"noopener\">Attempt Online<\/a><\/div>\n<\/div>\n<section id=\"pyq-correct-answer\">\nThe reaction given is CaO(s) + H\u2082O(l) \u2192 Ca(OH)\u2082(aq) + Heat. This is the slaking of quicklime (CaO) to produce slaked lime (Ca(OH)\u2082).<br \/>\nStatement 1: Quicklime (CaO) is used for white-washing of walls. While quicklime is the starting material, it is typically slaked with water to form calcium hydroxide (slaked lime) before being applied for whitewashing. So, this statement is not strictly accurate as CaO itself is not directly applied.<br \/>\nStatement 2: The solution of slaked lime (Ca(OH)\u2082) is used for whitewashing of walls. Correct. A suspension or solution of calcium hydroxide (slaked lime) is the material commonly applied as whitewash.<br \/>\nStatement 3: CaO reacts slowly with CO\u2082 in air to form a thin layer of CaCO\u2083 on walls. Incorrect. It is calcium hydroxide (slaked lime, Ca(OH)\u2082) that reacts with carbon dioxide in the air over time to form calcium carbonate (CaCO\u2083), which hardens and gives a shiny finish to the whitewash. CaO itself reacts readily with CO\u2082, but the reaction relevant to the setting of whitewash is between Ca(OH)\u2082 and CO\u2082.<br \/>\nStatement 4: Calcium hydroxide called \u2018slaked lime\u2019 is an inorganic compound. Correct. Calcium hydroxide is a compound of calcium, oxygen, and hydrogen, without carbon-hydrogen bonds, classifying it as an inorganic compound.<br \/>\nBased on the analysis, statements 2 and 4 are correct, and statements 1 and 3 are incorrect or less accurate.<br \/>\n<\/section>\n<section id=\"pyq-key-points\">\nSlaked lime (Ca(OH)\u2082) solution is used for whitewashing. Slaked lime reacts with CO\u2082 in air to form CaCO\u2083.<br \/>\n<\/section>\n<section id=\"pyq-additional-information\">\nThe process of whitewashing involves applying slaked lime (calcium hydroxide) to walls. The applied calcium hydroxide then reacts slowly with atmospheric carbon dioxide to form a hard layer of calcium carbonate, which is durable and provides a good white finish. CaO is also known as quicklime or burnt lime, and Ca(OH)\u2082 is also known as hydrated lime or slaked lime.<br \/>\n<\/section>\n","protected":false},"excerpt":{"rendered":"<p>Which of the following statements with regard to the reaction given below are correct? CaO(s) + H\u2082O(l) \u2192 Ca(OH)\u2082(aq) + Heat 1. Quicklime is used for white-washing of walls. 2. The solution of slaked lime is used for whitewashing of walls. 3. CaO reacts slowly with CO\u2082 in air to form a thin layer of &#8230; <\/p>\n<p class=\"read-more-container\"><a title=\"Which of the following statements with regard to the reaction given be\" class=\"read-more button\" href=\"https:\/\/exam.pscnotes.com\/mcq\/which-of-the-following-statements-with-regard-to-the-reaction-given-be\/#more-85343\">Detailed Solution<span class=\"screen-reader-text\">Which of the following statements with regard to the reaction given be<\/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":[1105,1096,1239],"class_list":["post-85343","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1105","tag-chemistry","tag-inorganic-chemistry","no-featured-image-padding"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v22.2 (Yoast SEO v23.3) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Which of the following statements with regard to the reaction given be<\/title>\n<meta name=\"description\" content=\"The reaction given is CaO(s) + H\u2082O(l) \u2192 Ca(OH)\u2082(aq) + Heat. This is the slaking of quicklime (CaO) to produce slaked lime (Ca(OH)\u2082). Statement 1: Quicklime (CaO) is used for white-washing of walls. While quicklime is the starting material, it is typically slaked with water to form calcium hydroxide (slaked lime) before being applied for whitewashing. So, this statement is not strictly accurate as CaO itself is not directly applied. Statement 2: The solution of slaked lime (Ca(OH)\u2082) is used for whitewashing of walls. Correct. A suspension or solution of calcium hydroxide (slaked lime) is the material commonly applied as whitewash. Statement 3: CaO reacts slowly with CO\u2082 in air to form a thin layer of CaCO\u2083 on walls. Incorrect. It is calcium hydroxide (slaked lime, Ca(OH)\u2082) that reacts with carbon dioxide in the air over time to form calcium carbonate (CaCO\u2083), which hardens and gives a shiny finish to the whitewash. CaO itself reacts readily with CO\u2082, but the reaction relevant to the setting of whitewash is between Ca(OH)\u2082 and CO\u2082. Statement 4: Calcium hydroxide called \u2018slaked lime\u2019 is an inorganic compound. Correct. Calcium hydroxide is a compound of calcium, oxygen, and hydrogen, without carbon-hydrogen bonds, classifying it as an inorganic compound. Based on the analysis, statements 2 and 4 are correct, and statements 1 and 3 are incorrect or less accurate. Slaked lime (Ca(OH)\u2082) solution is used for whitewashing. Slaked lime reacts with CO\u2082 in air to form CaCO\u2083.\" \/>\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-of-the-following-statements-with-regard-to-the-reaction-given-be\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Which of the following statements with regard to the reaction given be\" \/>\n<meta property=\"og:description\" content=\"The reaction given is CaO(s) + H\u2082O(l) \u2192 Ca(OH)\u2082(aq) + Heat. This is the slaking of quicklime (CaO) to produce slaked lime (Ca(OH)\u2082). Statement 1: Quicklime (CaO) is used for white-washing of walls. While quicklime is the starting material, it is typically slaked with water to form calcium hydroxide (slaked lime) before being applied for whitewashing. So, this statement is not strictly accurate as CaO itself is not directly applied. Statement 2: The solution of slaked lime (Ca(OH)\u2082) is used for whitewashing of walls. Correct. A suspension or solution of calcium hydroxide (slaked lime) is the material commonly applied as whitewash. Statement 3: CaO reacts slowly with CO\u2082 in air to form a thin layer of CaCO\u2083 on walls. Incorrect. It is calcium hydroxide (slaked lime, Ca(OH)\u2082) that reacts with carbon dioxide in the air over time to form calcium carbonate (CaCO\u2083), which hardens and gives a shiny finish to the whitewash. CaO itself reacts readily with CO\u2082, but the reaction relevant to the setting of whitewash is between Ca(OH)\u2082 and CO\u2082. Statement 4: Calcium hydroxide called \u2018slaked lime\u2019 is an inorganic compound. Correct. Calcium hydroxide is a compound of calcium, oxygen, and hydrogen, without carbon-hydrogen bonds, classifying it as an inorganic compound. Based on the analysis, statements 2 and 4 are correct, and statements 1 and 3 are incorrect or less accurate. Slaked lime (Ca(OH)\u2082) solution is used for whitewashing. Slaked lime reacts with CO\u2082 in air to form CaCO\u2083.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-of-the-following-statements-with-regard-to-the-reaction-given-be\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T03:12:44+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 of the following statements with regard to the reaction given be","description":"The reaction given is CaO(s) + H\u2082O(l) \u2192 Ca(OH)\u2082(aq) + Heat. This is the slaking of quicklime (CaO) to produce slaked lime (Ca(OH)\u2082). Statement 1: Quicklime (CaO) is used for white-washing of walls. While quicklime is the starting material, it is typically slaked with water to form calcium hydroxide (slaked lime) before being applied for whitewashing. So, this statement is not strictly accurate as CaO itself is not directly applied. Statement 2: The solution of slaked lime (Ca(OH)\u2082) is used for whitewashing of walls. Correct. A suspension or solution of calcium hydroxide (slaked lime) is the material commonly applied as whitewash. Statement 3: CaO reacts slowly with CO\u2082 in air to form a thin layer of CaCO\u2083 on walls. Incorrect. It is calcium hydroxide (slaked lime, Ca(OH)\u2082) that reacts with carbon dioxide in the air over time to form calcium carbonate (CaCO\u2083), which hardens and gives a shiny finish to the whitewash. CaO itself reacts readily with CO\u2082, but the reaction relevant to the setting of whitewash is between Ca(OH)\u2082 and CO\u2082. Statement 4: Calcium hydroxide called \u2018slaked lime\u2019 is an inorganic compound. Correct. Calcium hydroxide is a compound of calcium, oxygen, and hydrogen, without carbon-hydrogen bonds, classifying it as an inorganic compound. Based on the analysis, statements 2 and 4 are correct, and statements 1 and 3 are incorrect or less accurate. Slaked lime (Ca(OH)\u2082) solution is used for whitewashing. Slaked lime reacts with CO\u2082 in air to form CaCO\u2083.","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-of-the-following-statements-with-regard-to-the-reaction-given-be\/","og_locale":"en_US","og_type":"article","og_title":"Which of the following statements with regard to the reaction given be","og_description":"The reaction given is CaO(s) + H\u2082O(l) \u2192 Ca(OH)\u2082(aq) + Heat. This is the slaking of quicklime (CaO) to produce slaked lime (Ca(OH)\u2082). Statement 1: Quicklime (CaO) is used for white-washing of walls. While quicklime is the starting material, it is typically slaked with water to form calcium hydroxide (slaked lime) before being applied for whitewashing. So, this statement is not strictly accurate as CaO itself is not directly applied. Statement 2: The solution of slaked lime (Ca(OH)\u2082) is used for whitewashing of walls. Correct. A suspension or solution of calcium hydroxide (slaked lime) is the material commonly applied as whitewash. Statement 3: CaO reacts slowly with CO\u2082 in air to form a thin layer of CaCO\u2083 on walls. Incorrect. It is calcium hydroxide (slaked lime, Ca(OH)\u2082) that reacts with carbon dioxide in the air over time to form calcium carbonate (CaCO\u2083), which hardens and gives a shiny finish to the whitewash. CaO itself reacts readily with CO\u2082, but the reaction relevant to the setting of whitewash is between Ca(OH)\u2082 and CO\u2082. Statement 4: Calcium hydroxide called \u2018slaked lime\u2019 is an inorganic compound. Correct. Calcium hydroxide is a compound of calcium, oxygen, and hydrogen, without carbon-hydrogen bonds, classifying it as an inorganic compound. Based on the analysis, statements 2 and 4 are correct, and statements 1 and 3 are incorrect or less accurate. Slaked lime (Ca(OH)\u2082) solution is used for whitewashing. Slaked lime reacts with CO\u2082 in air to form CaCO\u2083.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/which-of-the-following-statements-with-regard-to-the-reaction-given-be\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T03:12:44+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-of-the-following-statements-with-regard-to-the-reaction-given-be\/","url":"https:\/\/exam.pscnotes.com\/mcq\/which-of-the-following-statements-with-regard-to-the-reaction-given-be\/","name":"Which of the following statements with regard to the reaction given be","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T03:12:44+00:00","dateModified":"2025-06-01T03:12:44+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The reaction given is CaO(s) + H\u2082O(l) \u2192 Ca(OH)\u2082(aq) + Heat. This is the slaking of quicklime (CaO) to produce slaked lime (Ca(OH)\u2082). Statement 1: Quicklime (CaO) is used for white-washing of walls. While quicklime is the starting material, it is typically slaked with water to form calcium hydroxide (slaked lime) before being applied for whitewashing. So, this statement is not strictly accurate as CaO itself is not directly applied. Statement 2: The solution of slaked lime (Ca(OH)\u2082) is used for whitewashing of walls. Correct. A suspension or solution of calcium hydroxide (slaked lime) is the material commonly applied as whitewash. Statement 3: CaO reacts slowly with CO\u2082 in air to form a thin layer of CaCO\u2083 on walls. Incorrect. It is calcium hydroxide (slaked lime, Ca(OH)\u2082) that reacts with carbon dioxide in the air over time to form calcium carbonate (CaCO\u2083), which hardens and gives a shiny finish to the whitewash. CaO itself reacts readily with CO\u2082, but the reaction relevant to the setting of whitewash is between Ca(OH)\u2082 and CO\u2082. Statement 4: Calcium hydroxide called \u2018slaked lime\u2019 is an inorganic compound. Correct. Calcium hydroxide is a compound of calcium, oxygen, and hydrogen, without carbon-hydrogen bonds, classifying it as an inorganic compound. Based on the analysis, statements 2 and 4 are correct, and statements 1 and 3 are incorrect or less accurate. Slaked lime (Ca(OH)\u2082) solution is used for whitewashing. Slaked lime reacts with CO\u2082 in air to form CaCO\u2083.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/which-of-the-following-statements-with-regard-to-the-reaction-given-be\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/which-of-the-following-statements-with-regard-to-the-reaction-given-be\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-of-the-following-statements-with-regard-to-the-reaction-given-be\/#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":"Which of the following statements with regard to the reaction given be"}]},{"@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\/85343","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=85343"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/85343\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=85343"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=85343"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=85343"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}