{"id":86168,"date":"2025-06-01T03:39:19","date_gmt":"2025-06-01T03:39:19","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=86168"},"modified":"2025-06-01T03:39:19","modified_gmt":"2025-06-01T03:39:19","slug":"when-copper-reacts-with-moist-carbon-dioxide-co%e2%82%82-in-air-it-forms-a","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/when-copper-reacts-with-moist-carbon-dioxide-co%e2%82%82-in-air-it-forms-a\/","title":{"rendered":"When copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a"},"content":{"rendered":"

When copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a green coating of which one of the following compounds ?<\/p>\n

[amp_mcq option1=”Cupric carbonate” option2=”Cuprous oxide” option3=”Cupric oxide” option4=”Copper sulphate” correct=”option1″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC CDS-2 – 2021<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nWhen copper is exposed to the atmosphere, it reacts with components in the air, including moisture (H\u2082O), oxygen (O\u2082), and carbon dioxide (CO\u2082). This reaction leads to the formation of a green layer known as patina. The primary chemical compound responsible for this green colour is basic copper carbonate, with the formula generally represented as Cu\u2082(OH)\u2082CO\u2083 (malachite) or Cu\u2083(OH)\u2082(CO\u2083)\u2082 (azurite, blue, often found mixed with malachite) or a mixture of Cu(OH)\u2082 and CuCO\u2083. The term “cupric carbonate” refers to Copper(II) carbonate, CuCO\u2083. While the patina is technically *basic* copper carbonate, Cu\u2082(OH)\u2082CO\u2083, which is a compound containing both hydroxide and carbonate, among the given options, “Cupric carbonate” is the closest description of the carbonate component that gives the green colour, often formed via the reaction:
\n2Cu(s) + H\u2082O(g) + CO\u2082(g) + O\u2082(g) \u2192 Cu\u2082(OH)\u2082CO\u2083(s)
\nCupric means Copper(II). Option A correctly identifies the compound as a form of copper carbonate.
\n<\/section>\n
\n– The green coating on copper exposed to air is called patina.
\n– Patina is formed by the reaction of copper with moisture, oxygen, and carbon dioxide.
\n– The main component of green patina is basic copper carbonate.
\n<\/section>\n
\nOther compounds listed: Cuprous oxide (Cu\u2082O) is reddish-brown. Cupric oxide (CuO) is black. Copper sulphate (CuSO\u2084) is a blue crystalline solid or white powder and is soluble in water; it wouldn’t typically form a persistent green coating from atmospheric exposure alone unless sulphur dioxide is also present, forming basic copper sulfate.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

When copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a green coating of which one of the following compounds ? [amp_mcq option1=”Cupric carbonate” option2=”Cuprous oxide” option3=”Cupric oxide” option4=”Copper sulphate” correct=”option1″] This question was previously asked in UPSC CDS-2 – 2021 Download PDFAttempt Online When copper is exposed to the atmosphere, it reacts … <\/p>\n

Detailed SolutionWhen copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a<\/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":[1110,1096,1109],"class_list":["post-86168","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-2","tag-1110","tag-chemistry","tag-metals-minerals-ores-properties-uses","no-featured-image-padding"],"yoast_head":"\nWhen copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a<\/title>\n<meta name=\"description\" content=\"When copper is exposed to the atmosphere, it reacts with components in the air, including moisture (H\u2082O), oxygen (O\u2082), and carbon dioxide (CO\u2082). This reaction leads to the formation of a green layer known as patina. The primary chemical compound responsible for this green colour is basic copper carbonate, with the formula generally represented as Cu\u2082(OH)\u2082CO\u2083 (malachite) or Cu\u2083(OH)\u2082(CO\u2083)\u2082 (azurite, blue, often found mixed with malachite) or a mixture of Cu(OH)\u2082 and CuCO\u2083. The term "cupric carbonate" refers to Copper(II) carbonate, CuCO\u2083. While the patina is technically *basic* copper carbonate, Cu\u2082(OH)\u2082CO\u2083, which is a compound containing both hydroxide and carbonate, among the given options, "Cupric carbonate" is the closest description of the carbonate component that gives the green colour, often formed via the reaction: 2Cu(s) + H\u2082O(g) + CO\u2082(g) + O\u2082(g) \u2192 Cu\u2082(OH)\u2082CO\u2083(s) Cupric means Copper(II). Option A correctly identifies the compound as a form of copper carbonate. - The green coating on copper exposed to air is called patina. - Patina is formed by the reaction of copper with moisture, oxygen, and carbon dioxide. - The main component of green patina is basic copper carbonate.\" \/>\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\/when-copper-reacts-with-moist-carbon-dioxide-co\u2082-in-air-it-forms-a\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"When copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a\" \/>\n<meta property=\"og:description\" content=\"When copper is exposed to the atmosphere, it reacts with components in the air, including moisture (H\u2082O), oxygen (O\u2082), and carbon dioxide (CO\u2082). This reaction leads to the formation of a green layer known as patina. The primary chemical compound responsible for this green colour is basic copper carbonate, with the formula generally represented as Cu\u2082(OH)\u2082CO\u2083 (malachite) or Cu\u2083(OH)\u2082(CO\u2083)\u2082 (azurite, blue, often found mixed with malachite) or a mixture of Cu(OH)\u2082 and CuCO\u2083. The term "cupric carbonate" refers to Copper(II) carbonate, CuCO\u2083. While the patina is technically *basic* copper carbonate, Cu\u2082(OH)\u2082CO\u2083, which is a compound containing both hydroxide and carbonate, among the given options, "Cupric carbonate" is the closest description of the carbonate component that gives the green colour, often formed via the reaction: 2Cu(s) + H\u2082O(g) + CO\u2082(g) + O\u2082(g) \u2192 Cu\u2082(OH)\u2082CO\u2083(s) Cupric means Copper(II). Option A correctly identifies the compound as a form of copper carbonate. - The green coating on copper exposed to air is called patina. - Patina is formed by the reaction of copper with moisture, oxygen, and carbon dioxide. - The main component of green patina is basic copper carbonate.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/when-copper-reacts-with-moist-carbon-dioxide-co\u2082-in-air-it-forms-a\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T03:39:19+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":"When copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a","description":"When copper is exposed to the atmosphere, it reacts with components in the air, including moisture (H\u2082O), oxygen (O\u2082), and carbon dioxide (CO\u2082). This reaction leads to the formation of a green layer known as patina. The primary chemical compound responsible for this green colour is basic copper carbonate, with the formula generally represented as Cu\u2082(OH)\u2082CO\u2083 (malachite) or Cu\u2083(OH)\u2082(CO\u2083)\u2082 (azurite, blue, often found mixed with malachite) or a mixture of Cu(OH)\u2082 and CuCO\u2083. The term \"cupric carbonate\" refers to Copper(II) carbonate, CuCO\u2083. While the patina is technically *basic* copper carbonate, Cu\u2082(OH)\u2082CO\u2083, which is a compound containing both hydroxide and carbonate, among the given options, \"Cupric carbonate\" is the closest description of the carbonate component that gives the green colour, often formed via the reaction: 2Cu(s) + H\u2082O(g) + CO\u2082(g) + O\u2082(g) \u2192 Cu\u2082(OH)\u2082CO\u2083(s) Cupric means Copper(II). Option A correctly identifies the compound as a form of copper carbonate. - The green coating on copper exposed to air is called patina. - Patina is formed by the reaction of copper with moisture, oxygen, and carbon dioxide. - The main component of green patina is basic copper carbonate.","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\/when-copper-reacts-with-moist-carbon-dioxide-co\u2082-in-air-it-forms-a\/","og_locale":"en_US","og_type":"article","og_title":"When copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a","og_description":"When copper is exposed to the atmosphere, it reacts with components in the air, including moisture (H\u2082O), oxygen (O\u2082), and carbon dioxide (CO\u2082). This reaction leads to the formation of a green layer known as patina. The primary chemical compound responsible for this green colour is basic copper carbonate, with the formula generally represented as Cu\u2082(OH)\u2082CO\u2083 (malachite) or Cu\u2083(OH)\u2082(CO\u2083)\u2082 (azurite, blue, often found mixed with malachite) or a mixture of Cu(OH)\u2082 and CuCO\u2083. The term \"cupric carbonate\" refers to Copper(II) carbonate, CuCO\u2083. While the patina is technically *basic* copper carbonate, Cu\u2082(OH)\u2082CO\u2083, which is a compound containing both hydroxide and carbonate, among the given options, \"Cupric carbonate\" is the closest description of the carbonate component that gives the green colour, often formed via the reaction: 2Cu(s) + H\u2082O(g) + CO\u2082(g) + O\u2082(g) \u2192 Cu\u2082(OH)\u2082CO\u2083(s) Cupric means Copper(II). Option A correctly identifies the compound as a form of copper carbonate. - The green coating on copper exposed to air is called patina. - Patina is formed by the reaction of copper with moisture, oxygen, and carbon dioxide. - The main component of green patina is basic copper carbonate.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/when-copper-reacts-with-moist-carbon-dioxide-co\u2082-in-air-it-forms-a\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T03:39:19+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\/when-copper-reacts-with-moist-carbon-dioxide-co%e2%82%82-in-air-it-forms-a\/","url":"https:\/\/exam.pscnotes.com\/mcq\/when-copper-reacts-with-moist-carbon-dioxide-co%e2%82%82-in-air-it-forms-a\/","name":"When copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T03:39:19+00:00","dateModified":"2025-06-01T03:39:19+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"When copper is exposed to the atmosphere, it reacts with components in the air, including moisture (H\u2082O), oxygen (O\u2082), and carbon dioxide (CO\u2082). This reaction leads to the formation of a green layer known as patina. The primary chemical compound responsible for this green colour is basic copper carbonate, with the formula generally represented as Cu\u2082(OH)\u2082CO\u2083 (malachite) or Cu\u2083(OH)\u2082(CO\u2083)\u2082 (azurite, blue, often found mixed with malachite) or a mixture of Cu(OH)\u2082 and CuCO\u2083. The term \"cupric carbonate\" refers to Copper(II) carbonate, CuCO\u2083. While the patina is technically *basic* copper carbonate, Cu\u2082(OH)\u2082CO\u2083, which is a compound containing both hydroxide and carbonate, among the given options, \"Cupric carbonate\" is the closest description of the carbonate component that gives the green colour, often formed via the reaction: 2Cu(s) + H\u2082O(g) + CO\u2082(g) + O\u2082(g) \u2192 Cu\u2082(OH)\u2082CO\u2083(s) Cupric means Copper(II). Option A correctly identifies the compound as a form of copper carbonate. - The green coating on copper exposed to air is called patina. - Patina is formed by the reaction of copper with moisture, oxygen, and carbon dioxide. - The main component of green patina is basic copper carbonate.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/when-copper-reacts-with-moist-carbon-dioxide-co%e2%82%82-in-air-it-forms-a\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/when-copper-reacts-with-moist-carbon-dioxide-co%e2%82%82-in-air-it-forms-a\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/when-copper-reacts-with-moist-carbon-dioxide-co%e2%82%82-in-air-it-forms-a\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC CDS-2","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-cds-2\/"},{"@type":"ListItem","position":3,"name":"When copper reacts with moist carbon dioxide (CO\u2082) in air, it forms a"}]},{"@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\/86168","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=86168"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/86168\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=86168"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=86168"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=86168"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}