{"id":88482,"date":"2025-06-01T07:12:04","date_gmt":"2025-06-01T07:12:04","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=88482"},"modified":"2025-06-01T07:12:04","modified_gmt":"2025-06-01T07:12:04","slug":"which-one-of-the-following-is-an-oxidation-reduction-reaction","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-an-oxidation-reduction-reaction\/","title":{"rendered":"Which one of the following is an oxidation-reduction reaction?"},"content":{"rendered":"

Which one of the following is an oxidation-reduction reaction?<\/p>\n

[amp_mcq option1=”NaOH + HCl \u2192 NaCl + H\u2082O” option2=”CaO + H\u2082O \u2192 Ca(OH)\u2082” option3=”2Mg + O\u2082 \u2192 2MgO” option4=”Na\u2082SO\u2084 + BaCl\u2082 \u2192 BaSO\u2084 + 2NaCl” correct=”option3″]<\/p>\n

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This question was previously asked in<\/div>\n
UPSC NDA-2 – 2018<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nAn oxidation-reduction (redox) reaction is a chemical reaction in which the oxidation states of atoms are changed. This involves the transfer of electrons.
\nLet’s check the oxidation states of elements in each reaction:
\nA) NaOH + HCl \u2192 NaCl + H\u2082O: Na (+1\u2192+1), O (-2\u2192-2), H (+1\u2192+1), Cl (-1\u2192-1). No change in oxidation states. This is an acid-base neutralization reaction.
\nB) CaO + H\u2082O \u2192 Ca(OH)\u2082: Ca (+2\u2192+2), O (-2\u2192-2), H (+1\u2192+1). No change in oxidation states. This is a combination reaction.
\nC) 2Mg + O\u2082 \u2192 2MgO: Mg (0\u2192+2), O (0\u2192-2). Magnesium’s oxidation state increases from 0 to +2 (oxidation). Oxygen’s oxidation state decreases from 0 to -2 (reduction). This is a redox reaction.
\nD) Na\u2082SO\u2084 + BaCl\u2082 \u2192 BaSO\u2084 + 2NaCl: Na (+1\u2192+1), S (+6\u2192+6), O (-2\u2192-2), Ba (+2\u2192+2), Cl (-1\u2192-1). No change in oxidation states. This is a double displacement (precipitation) reaction.
\n<\/section>\n
\nRedox reactions are characterized by changes in the oxidation states of the participating atoms. Oxidation is the loss of electrons (increase in oxidation state), and reduction is the gain of electrons (decrease in oxidation state). Elemental substances (like Mg and O\u2082) have an oxidation state of 0.
\n<\/section>\n
\nMany common reactions are redox reactions, including combustion, corrosion, and cellular respiration. Acid-base neutralization and simple precipitation reactions typically do not involve changes in oxidation states and are therefore not redox reactions.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Which one of the following is an oxidation-reduction reaction? [amp_mcq option1=”NaOH + HCl \u2192 NaCl + H\u2082O” option2=”CaO + H\u2082O \u2192 Ca(OH)\u2082” option3=”2Mg + O\u2082 \u2192 2MgO” option4=”Na\u2082SO\u2084 + BaCl\u2082 \u2192 BaSO\u2084 + 2NaCl” correct=”option3″] This question was previously asked in UPSC NDA-2 – 2018 Download PDFAttempt Online An oxidation-reduction (redox) reaction is a chemical … <\/p>\n

Detailed SolutionWhich one of the following is an oxidation-reduction reaction?<\/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":[1114,1096,1155],"class_list":["post-88482","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-2","tag-1114","tag-chemistry","tag-physical-and-chemical-changes-solution","no-featured-image-padding"],"yoast_head":"\nWhich one of the following is an oxidation-reduction reaction?<\/title>\n<meta name=\"description\" content=\"An oxidation-reduction (redox) reaction is a chemical reaction in which the oxidation states of atoms are changed. This involves the transfer of electrons. Let's check the oxidation states of elements in each reaction: A) NaOH + HCl \u2192 NaCl + H\u2082O: Na (+1\u2192+1), O (-2\u2192-2), H (+1\u2192+1), Cl (-1\u2192-1). No change in oxidation states. This is an acid-base neutralization reaction. B) CaO + H\u2082O \u2192 Ca(OH)\u2082: Ca (+2\u2192+2), O (-2\u2192-2), H (+1\u2192+1). No change in oxidation states. This is a combination reaction. C) 2Mg + O\u2082 \u2192 2MgO: Mg (0\u2192+2), O (0\u2192-2). Magnesium's oxidation state increases from 0 to +2 (oxidation). Oxygen's oxidation state decreases from 0 to -2 (reduction). This is a redox reaction. D) Na\u2082SO\u2084 + BaCl\u2082 \u2192 BaSO\u2084 + 2NaCl: Na (+1\u2192+1), S (+6\u2192+6), O (-2\u2192-2), Ba (+2\u2192+2), Cl (-1\u2192-1). No change in oxidation states. This is a double displacement (precipitation) reaction. Redox reactions are characterized by changes in the oxidation states of the participating atoms. Oxidation is the loss of electrons (increase in oxidation state), and reduction is the gain of electrons (decrease in oxidation state). Elemental substances (like Mg and O\u2082) have an oxidation state of 0.\" \/>\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-is-an-oxidation-reduction-reaction\/\" \/>\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 is an oxidation-reduction reaction?\" \/>\n<meta property=\"og:description\" content=\"An oxidation-reduction (redox) reaction is a chemical reaction in which the oxidation states of atoms are changed. This involves the transfer of electrons. Let's check the oxidation states of elements in each reaction: A) NaOH + HCl \u2192 NaCl + H\u2082O: Na (+1\u2192+1), O (-2\u2192-2), H (+1\u2192+1), Cl (-1\u2192-1). No change in oxidation states. This is an acid-base neutralization reaction. B) CaO + H\u2082O \u2192 Ca(OH)\u2082: Ca (+2\u2192+2), O (-2\u2192-2), H (+1\u2192+1). No change in oxidation states. This is a combination reaction. C) 2Mg + O\u2082 \u2192 2MgO: Mg (0\u2192+2), O (0\u2192-2). Magnesium's oxidation state increases from 0 to +2 (oxidation). Oxygen's oxidation state decreases from 0 to -2 (reduction). This is a redox reaction. D) Na\u2082SO\u2084 + BaCl\u2082 \u2192 BaSO\u2084 + 2NaCl: Na (+1\u2192+1), S (+6\u2192+6), O (-2\u2192-2), Ba (+2\u2192+2), Cl (-1\u2192-1). No change in oxidation states. This is a double displacement (precipitation) reaction. Redox reactions are characterized by changes in the oxidation states of the participating atoms. Oxidation is the loss of electrons (increase in oxidation state), and reduction is the gain of electrons (decrease in oxidation state). Elemental substances (like Mg and O\u2082) have an oxidation state of 0.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-an-oxidation-reduction-reaction\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T07:12:04+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 is an oxidation-reduction reaction?","description":"An oxidation-reduction (redox) reaction is a chemical reaction in which the oxidation states of atoms are changed. This involves the transfer of electrons. Let's check the oxidation states of elements in each reaction: A) NaOH + HCl \u2192 NaCl + H\u2082O: Na (+1\u2192+1), O (-2\u2192-2), H (+1\u2192+1), Cl (-1\u2192-1). No change in oxidation states. This is an acid-base neutralization reaction. B) CaO + H\u2082O \u2192 Ca(OH)\u2082: Ca (+2\u2192+2), O (-2\u2192-2), H (+1\u2192+1). No change in oxidation states. This is a combination reaction. C) 2Mg + O\u2082 \u2192 2MgO: Mg (0\u2192+2), O (0\u2192-2). Magnesium's oxidation state increases from 0 to +2 (oxidation). Oxygen's oxidation state decreases from 0 to -2 (reduction). This is a redox reaction. D) Na\u2082SO\u2084 + BaCl\u2082 \u2192 BaSO\u2084 + 2NaCl: Na (+1\u2192+1), S (+6\u2192+6), O (-2\u2192-2), Ba (+2\u2192+2), Cl (-1\u2192-1). No change in oxidation states. This is a double displacement (precipitation) reaction. Redox reactions are characterized by changes in the oxidation states of the participating atoms. Oxidation is the loss of electrons (increase in oxidation state), and reduction is the gain of electrons (decrease in oxidation state). Elemental substances (like Mg and O\u2082) have an oxidation state of 0.","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-is-an-oxidation-reduction-reaction\/","og_locale":"en_US","og_type":"article","og_title":"Which one of the following is an oxidation-reduction reaction?","og_description":"An oxidation-reduction (redox) reaction is a chemical reaction in which the oxidation states of atoms are changed. This involves the transfer of electrons. Let's check the oxidation states of elements in each reaction: A) NaOH + HCl \u2192 NaCl + H\u2082O: Na (+1\u2192+1), O (-2\u2192-2), H (+1\u2192+1), Cl (-1\u2192-1). No change in oxidation states. This is an acid-base neutralization reaction. B) CaO + H\u2082O \u2192 Ca(OH)\u2082: Ca (+2\u2192+2), O (-2\u2192-2), H (+1\u2192+1). No change in oxidation states. This is a combination reaction. C) 2Mg + O\u2082 \u2192 2MgO: Mg (0\u2192+2), O (0\u2192-2). Magnesium's oxidation state increases from 0 to +2 (oxidation). Oxygen's oxidation state decreases from 0 to -2 (reduction). This is a redox reaction. D) Na\u2082SO\u2084 + BaCl\u2082 \u2192 BaSO\u2084 + 2NaCl: Na (+1\u2192+1), S (+6\u2192+6), O (-2\u2192-2), Ba (+2\u2192+2), Cl (-1\u2192-1). No change in oxidation states. This is a double displacement (precipitation) reaction. Redox reactions are characterized by changes in the oxidation states of the participating atoms. Oxidation is the loss of electrons (increase in oxidation state), and reduction is the gain of electrons (decrease in oxidation state). Elemental substances (like Mg and O\u2082) have an oxidation state of 0.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-an-oxidation-reduction-reaction\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T07:12:04+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\/which-one-of-the-following-is-an-oxidation-reduction-reaction\/","url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-an-oxidation-reduction-reaction\/","name":"Which one of the following is an oxidation-reduction reaction?","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T07:12:04+00:00","dateModified":"2025-06-01T07:12:04+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"An oxidation-reduction (redox) reaction is a chemical reaction in which the oxidation states of atoms are changed. This involves the transfer of electrons. Let's check the oxidation states of elements in each reaction: A) NaOH + HCl \u2192 NaCl + H\u2082O: Na (+1\u2192+1), O (-2\u2192-2), H (+1\u2192+1), Cl (-1\u2192-1). No change in oxidation states. This is an acid-base neutralization reaction. B) CaO + H\u2082O \u2192 Ca(OH)\u2082: Ca (+2\u2192+2), O (-2\u2192-2), H (+1\u2192+1). No change in oxidation states. This is a combination reaction. C) 2Mg + O\u2082 \u2192 2MgO: Mg (0\u2192+2), O (0\u2192-2). Magnesium's oxidation state increases from 0 to +2 (oxidation). Oxygen's oxidation state decreases from 0 to -2 (reduction). This is a redox reaction. D) Na\u2082SO\u2084 + BaCl\u2082 \u2192 BaSO\u2084 + 2NaCl: Na (+1\u2192+1), S (+6\u2192+6), O (-2\u2192-2), Ba (+2\u2192+2), Cl (-1\u2192-1). No change in oxidation states. This is a double displacement (precipitation) reaction. Redox reactions are characterized by changes in the oxidation states of the participating atoms. Oxidation is the loss of electrons (increase in oxidation state), and reduction is the gain of electrons (decrease in oxidation state). Elemental substances (like Mg and O\u2082) have an oxidation state of 0.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-an-oxidation-reduction-reaction\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-an-oxidation-reduction-reaction\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-is-an-oxidation-reduction-reaction\/#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 is an oxidation-reduction reaction?"}]},{"@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\/88482","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=88482"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/88482\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=88482"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=88482"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=88482"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}