{"id":85206,"date":"2025-06-01T03:07:48","date_gmt":"2025-06-01T03:07:48","guid":{"rendered":"https:\/\/exam.pscnotes.com\/mcq\/?p=85206"},"modified":"2025-06-01T03:07:48","modified_gmt":"2025-06-01T03:07:48","slug":"which-one-of-the-following-sodium-compounds-is-used-for-softening-hard","status":"publish","type":"post","link":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-sodium-compounds-is-used-for-softening-hard\/","title":{"rendered":"Which one of the following sodium compounds is used for softening hard"},"content":{"rendered":"

Which one of the following sodium compounds is used for softening hard water ?<\/p>\n

[amp_mcq option1=”Na\u2082CO\u2083” option2=”NaHCO\u2083” option3=”NaOH” option4=”Na\u2082SO\u2084” correct=”option1″]<\/p>\n

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This question was previously asked in<\/div>\n
UPSC CDS-1 – 2021<\/div>\n<\/div>\n
Download PDF<\/a>Attempt Online<\/a><\/div>\n<\/div>\n
\nHard water contains dissolved minerals, primarily calcium and magnesium ions. Sodium carbonate (Na\u2082CO\u2083), also known as washing soda, is commonly used to soften hard water by removing these ions.
\n<\/section>\n
\nWhen sodium carbonate is added to hard water, the calcium and magnesium ions react with the carbonate ions to form insoluble calcium carbonate (CaCO\u2083) and magnesium carbonate (MgCO\u2083). These precipitates settle down or can be filtered out, effectively reducing the concentration of hardening ions in the water. The overall reaction with calcium ions is: Ca\u00b2\u207a(aq) + Na\u2082CO\u2083(aq) \u2192 CaCO\u2083(s) + 2Na\u207a(aq). The resulting sodium ions (Na\u207a) do not contribute to water hardness.
\n<\/section>\n
\nOther methods for water softening include using ion-exchange resins, which swap calcium and magnesium ions for sodium ions, or using chelating agents that bind the metal ions. While boiling can remove temporary hardness (caused by bicarbonates), it does not remove permanent hardness (caused by sulfates and chlorides), which sodium carbonate can address.
\n<\/section>\n","protected":false},"excerpt":{"rendered":"

Which one of the following sodium compounds is used for softening hard water ? [amp_mcq option1=”Na\u2082CO\u2083” option2=”NaHCO\u2083” option3=”NaOH” option4=”Na\u2082SO\u2084” correct=”option1″] This question was previously asked in UPSC CDS-1 – 2021 Download PDFAttempt Online Hard water contains dissolved minerals, primarily calcium and magnesium ions. Sodium carbonate (Na\u2082CO\u2083), also known as washing soda, is commonly used to … <\/p>\n

Detailed SolutionWhich one of the following sodium compounds is used for softening hard<\/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":[1110,1202,1096],"class_list":["post-85206","post","type-post","status-publish","format-standard","hentry","category-upsc-cds-1","tag-1110","tag-acid-base-and-salt","tag-chemistry","no-featured-image-padding"],"yoast_head":"\nWhich one of the following sodium compounds is used for softening hard<\/title>\n<meta name=\"description\" content=\"Hard water contains dissolved minerals, primarily calcium and magnesium ions. Sodium carbonate (Na\u2082CO\u2083), also known as washing soda, is commonly used to soften hard water by removing these ions. When sodium carbonate is added to hard water, the calcium and magnesium ions react with the carbonate ions to form insoluble calcium carbonate (CaCO\u2083) and magnesium carbonate (MgCO\u2083). These precipitates settle down or can be filtered out, effectively reducing the concentration of hardening ions in the water. The overall reaction with calcium ions is: Ca\u00b2\u207a(aq) + Na\u2082CO\u2083(aq) \u2192 CaCO\u2083(s) + 2Na\u207a(aq). The resulting sodium ions (Na\u207a) do not contribute to water hardness.\" \/>\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-sodium-compounds-is-used-for-softening-hard\/\" \/>\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 sodium compounds is used for softening hard\" \/>\n<meta property=\"og:description\" content=\"Hard water contains dissolved minerals, primarily calcium and magnesium ions. Sodium carbonate (Na\u2082CO\u2083), also known as washing soda, is commonly used to soften hard water by removing these ions. When sodium carbonate is added to hard water, the calcium and magnesium ions react with the carbonate ions to form insoluble calcium carbonate (CaCO\u2083) and magnesium carbonate (MgCO\u2083). These precipitates settle down or can be filtered out, effectively reducing the concentration of hardening ions in the water. The overall reaction with calcium ions is: Ca\u00b2\u207a(aq) + Na\u2082CO\u2083(aq) \u2192 CaCO\u2083(s) + 2Na\u207a(aq). The resulting sodium ions (Na\u207a) do not contribute to water hardness.\" \/>\n<meta property=\"og:url\" content=\"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-sodium-compounds-is-used-for-softening-hard\/\" \/>\n<meta property=\"og:site_name\" content=\"MCQ and Quiz for Exams\" \/>\n<meta property=\"article:published_time\" content=\"2025-06-01T03:07:48+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 sodium compounds is used for softening hard","description":"Hard water contains dissolved minerals, primarily calcium and magnesium ions. Sodium carbonate (Na\u2082CO\u2083), also known as washing soda, is commonly used to soften hard water by removing these ions. When sodium carbonate is added to hard water, the calcium and magnesium ions react with the carbonate ions to form insoluble calcium carbonate (CaCO\u2083) and magnesium carbonate (MgCO\u2083). These precipitates settle down or can be filtered out, effectively reducing the concentration of hardening ions in the water. The overall reaction with calcium ions is: Ca\u00b2\u207a(aq) + Na\u2082CO\u2083(aq) \u2192 CaCO\u2083(s) + 2Na\u207a(aq). The resulting sodium ions (Na\u207a) do not contribute to water hardness.","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-sodium-compounds-is-used-for-softening-hard\/","og_locale":"en_US","og_type":"article","og_title":"Which one of the following sodium compounds is used for softening hard","og_description":"Hard water contains dissolved minerals, primarily calcium and magnesium ions. Sodium carbonate (Na\u2082CO\u2083), also known as washing soda, is commonly used to soften hard water by removing these ions. When sodium carbonate is added to hard water, the calcium and magnesium ions react with the carbonate ions to form insoluble calcium carbonate (CaCO\u2083) and magnesium carbonate (MgCO\u2083). These precipitates settle down or can be filtered out, effectively reducing the concentration of hardening ions in the water. The overall reaction with calcium ions is: Ca\u00b2\u207a(aq) + Na\u2082CO\u2083(aq) \u2192 CaCO\u2083(s) + 2Na\u207a(aq). The resulting sodium ions (Na\u207a) do not contribute to water hardness.","og_url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-sodium-compounds-is-used-for-softening-hard\/","og_site_name":"MCQ and Quiz for Exams","article_published_time":"2025-06-01T03:07:48+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-sodium-compounds-is-used-for-softening-hard\/","url":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-sodium-compounds-is-used-for-softening-hard\/","name":"Which one of the following sodium compounds is used for softening hard","isPartOf":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#website"},"datePublished":"2025-06-01T03:07:48+00:00","dateModified":"2025-06-01T03:07:48+00:00","author":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/#\/schema\/person\/5807dafeb27d2ec82344d6cbd6c3d209"},"description":"Hard water contains dissolved minerals, primarily calcium and magnesium ions. 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The resulting sodium ions (Na\u207a) do not contribute to water hardness.","breadcrumb":{"@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-sodium-compounds-is-used-for-softening-hard\/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-sodium-compounds-is-used-for-softening-hard\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/exam.pscnotes.com\/mcq\/which-one-of-the-following-sodium-compounds-is-used-for-softening-hard\/#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 one of the following sodium compounds is used for softening hard"}]},{"@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\/85206","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=85206"}],"version-history":[{"count":0,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/posts\/85206\/revisions"}],"wp:attachment":[{"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/media?parent=85206"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/categories?post=85206"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exam.pscnotes.com\/mcq\/wp-json\/wp\/v2\/tags?post=85206"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}