{"id":87382,"date":"2025-06-01T06:42:05","date_gmt":"2025-06-01T06:42:05","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=87382"},"modified":"2025-06-01T06:42:05","modified_gmt":"2025-06-01T06:42:05","slug":"suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/","title":{"rendered":"Suppose you have four test tubes labelled as ‘A’, ‘B’, ‘C’ and ‘D’. ‘A"},"content":{"rendered":"

Suppose you have four test tubes labelled as ‘A’, ‘B’, ‘C’ and ‘D’. ‘A’ contains plain water, ‘B’ contains solution of an alkali, ‘C’ contains solution of an acid, and ‘D’ contains solution of sodium chloride. Which one of these solutions will turn phenolphthalein solution pink ?<\/p>\n

[amp_mcq option1=”Solution ‘A'” option2=”Solution ‘B'” option3=”Solution ‘C'” option4=”Solution ‘D'” correct=”option2″]<\/p>\n

\n
\n
This question was previously asked in<\/div>\n
UPSC NDA-1 – 2016<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nThe correct option is B.
\n<\/section>\n
\nPhenolphthalein is a common acid-base indicator. Its color changes depending on the pH of the solution:
\n– In acidic solutions (pH < ~8.2), phenolphthalein is colorless.\n- In neutral solutions (pH ~7), phenolphthalein is colorless.\n- In basic (alkaline) solutions (pH > ~8.2), phenolphthalein turns pink or magenta.
\nLet’s analyze the solutions:
\n– Solution ‘A’: Plain water is generally neutral (pH \u2248 7). Phenolphthalein will be colorless.
\n– Solution ‘B’: Solution of an alkali is basic. Phenolphthalein will turn pink.
\n– Solution ‘C’: Solution of an acid is acidic. Phenolphthalein will be colorless.
\n– Solution ‘D’: Solution of sodium chloride (NaCl) is the salt of a strong acid (HCl) and a strong base (NaOH). A solution of such a salt is neutral (pH \u2248 7). Phenolphthalein will be colorless.
\nTherefore, only the solution of an alkali (Solution ‘B’) will turn phenolphthalein solution pink.
\n<\/section>\n
\nIndicators are substances that show a change in color or some other property in response to a chemical change. Phenolphthalein is widely used in titrations to detect the endpoint of a reaction between an acid and a base. Different indicators change color at different pH ranges.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Suppose you have four test tubes labelled as ‘A’, ‘B’, ‘C’ and ‘D’. ‘A’ contains plain water, ‘B’ contains solution of an alkali, ‘C’ contains solution of an acid, and ‘D’ contains solution of sodium chloride. Which one of these solutions will turn phenolphthalein solution pink ? [amp_mcq option1=”Solution ‘A’” option2=”Solution ‘B’” option3=”Solution ‘C’” option4=”Solution … <\/p>\n

Detailed SolutionSuppose you have four test tubes labelled as ‘A’, ‘B’, ‘C’ and ‘D’. ‘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":[1093],"tags":[1098,1202,1096],"class_list":["post-87382","post","type-post","status-publish","format-standard","hentry","category-upsc-nda-1","tag-1098","tag-acid-base-and-salt","tag-chemistry","no-featured-image-padding"],"yoast_head":"\nSuppose you have four test tubes labelled as 'A', 'B', 'C' and 'D'. 'A<\/title>\n<meta name=\"description\" content=\"The correct option is B. Phenolphthalein is a common acid-base indicator. Its color changes depending on the pH of the solution: - In acidic solutions (pH < ~8.2), phenolphthalein is colorless. - In neutral solutions (pH ~7), phenolphthalein is colorless. - In basic (alkaline) solutions (pH > ~8.2), phenolphthalein turns pink or magenta. Let's analyze the solutions: - Solution 'A': Plain water is generally neutral (pH \u2248 7). Phenolphthalein will be colorless. - Solution 'B': Solution of an alkali is basic. Phenolphthalein will turn pink. - Solution 'C': Solution of an acid is acidic. Phenolphthalein will be colorless. - Solution 'D': Solution of sodium chloride (NaCl) is the salt of a strong acid (HCl) and a strong base (NaOH). A solution of such a salt is neutral (pH \u2248 7). Phenolphthalein will be colorless. Therefore, only the solution of an alkali (Solution 'B') will turn phenolphthalein solution pink.\" \/>\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\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Suppose you have four test tubes labelled as 'A', 'B', 'C' and 'D'. 'A\" \/>\n<meta property=\"og:description\" content=\"The correct option is B. Phenolphthalein is a common acid-base indicator. Its color changes depending on the pH of the solution: - In acidic solutions (pH < ~8.2), phenolphthalein is colorless. - In neutral solutions (pH ~7), phenolphthalein is colorless. - In basic (alkaline) solutions (pH > ~8.2), phenolphthalein turns pink or magenta. Let's analyze the solutions: - Solution 'A': Plain water is generally neutral (pH \u2248 7). Phenolphthalein will be colorless. - Solution 'B': Solution of an alkali is basic. Phenolphthalein will turn pink. - Solution 'C': Solution of an acid is acidic. Phenolphthalein will be colorless. - Solution 'D': Solution of sodium chloride (NaCl) is the salt of a strong acid (HCl) and a strong base (NaOH). A solution of such a salt is neutral (pH \u2248 7). Phenolphthalein will be colorless. Therefore, only the solution of an alkali (Solution 'B') will turn phenolphthalein solution pink.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T06:42:05+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":"Suppose you have four test tubes labelled as 'A', 'B', 'C' and 'D'. 'A","description":"The correct option is B. Phenolphthalein is a common acid-base indicator. Its color changes depending on the pH of the solution: - In acidic solutions (pH < ~8.2), phenolphthalein is colorless. - In neutral solutions (pH ~7), phenolphthalein is colorless. - In basic (alkaline) solutions (pH > ~8.2), phenolphthalein turns pink or magenta. Let's analyze the solutions: - Solution 'A': Plain water is generally neutral (pH \u2248 7). Phenolphthalein will be colorless. - Solution 'B': Solution of an alkali is basic. Phenolphthalein will turn pink. - Solution 'C': Solution of an acid is acidic. Phenolphthalein will be colorless. - Solution 'D': Solution of sodium chloride (NaCl) is the salt of a strong acid (HCl) and a strong base (NaOH). A solution of such a salt is neutral (pH \u2248 7). Phenolphthalein will be colorless. Therefore, only the solution of an alkali (Solution 'B') will turn phenolphthalein solution pink.","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\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/","og_locale":"en_US","og_type":"article","og_title":"Suppose you have four test tubes labelled as 'A', 'B', 'C' and 'D'. 'A","og_description":"The correct option is B. Phenolphthalein is a common acid-base indicator. Its color changes depending on the pH of the solution: - In acidic solutions (pH < ~8.2), phenolphthalein is colorless. - In neutral solutions (pH ~7), phenolphthalein is colorless. - In basic (alkaline) solutions (pH > ~8.2), phenolphthalein turns pink or magenta. Let's analyze the solutions: - Solution 'A': Plain water is generally neutral (pH \u2248 7). Phenolphthalein will be colorless. - Solution 'B': Solution of an alkali is basic. Phenolphthalein will turn pink. - Solution 'C': Solution of an acid is acidic. Phenolphthalein will be colorless. - Solution 'D': Solution of sodium chloride (NaCl) is the salt of a strong acid (HCl) and a strong base (NaOH). A solution of such a salt is neutral (pH \u2248 7). Phenolphthalein will be colorless. Therefore, only the solution of an alkali (Solution 'B') will turn phenolphthalein solution pink.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T06:42:05+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\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/","url":"https:\/\/exam.pscnotes.com\/mcq\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/","name":"Suppose you have four test tubes labelled as 'A', 'B', 'C' and 'D'. 'A","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T06:42:05+00:00","dateModified":"2025-06-01T06:42:05+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"The correct option is B. Phenolphthalein is a common acid-base indicator. Its color changes depending on the pH of the solution: - In acidic solutions (pH < ~8.2), phenolphthalein is colorless. - In neutral solutions (pH ~7), phenolphthalein is colorless. - In basic (alkaline) solutions (pH > ~8.2), phenolphthalein turns pink or magenta. Let's analyze the solutions: - Solution 'A': Plain water is generally neutral (pH \u2248 7). Phenolphthalein will be colorless. - Solution 'B': Solution of an alkali is basic. Phenolphthalein will turn pink. - Solution 'C': Solution of an acid is acidic. Phenolphthalein will be colorless. - Solution 'D': Solution of sodium chloride (NaCl) is the salt of a strong acid (HCl) and a strong base (NaOH). A solution of such a salt is neutral (pH \u2248 7). Phenolphthalein will be colorless. Therefore, only the solution of an alkali (Solution 'B') will turn phenolphthalein solution pink.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/suppose-you-have-four-test-tubes-labelled-as-a-b-c-and-d-a\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/exam.pscnotes.com\/mcq\/"},{"@type":"ListItem","position":2,"name":"UPSC NDA-1","item":"https:\/\/exam.pscnotes.com\/mcq\/category\/upsc-nda-1\/"},{"@type":"ListItem","position":3,"name":"Suppose you have four test tubes labelled as ‘A’, ‘B’, ‘C’ and ‘D’. ‘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\/87382","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=87382"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/87382\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=87382"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=87382"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=87382"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}