{"id":1576,"date":"2025-05-28T07:47:18","date_gmt":"2025-05-28T07:47:18","guid":{"rendered":"https:\/\/medpharma12.com\/?p=1576"},"modified":"2025-06-10T04:37:06","modified_gmt":"2025-06-10T04:37:06","slug":"qualitative-analysis-of-unknown-organic-compound-for-detection-of-carbohydrate","status":"publish","type":"post","link":"https:\/\/medpharma12.com\/index.php\/2025\/05\/28\/qualitative-analysis-of-unknown-organic-compound-for-detection-of-carbohydrate\/","title":{"rendered":"Qualitative Analysis of unknown organic compound for detection of carbohydrate"},"content":{"rendered":"

Experiment No. 5<\/strong><\/span><\/p>\n

Objective<\/strong><\/span><\/p>\n

Qualitative Analysis of unknown organic compound for detection of carbohydrate<\/span><\/p>\n

References:<\/strong><\/span><\/p>\n

    \n
  1. Dr. Jain K.S., Dr. Miniyar P.B., A practical book of Pharmaceutical organic chemistry , Nirali publication, edition 4th, page No. 1.31-1.33<\/span><\/li>\n
  2. Vogel Arthere, Elementary practical organic chemistry, 2nd edition, 1966, published by CBS publisher, page No. 89<\/span><\/li>\n<\/ol>\n

    Requirement<\/strong><\/span><\/p>\n

    Glasswares and Instrument<\/strong><\/em><\/span><\/p>\n

      \n
    1. Test tubes<\/span><\/li>\n
    2. Pipette or dropper<\/span><\/li>\n
    3. Beaker (for water bath)<\/span><\/li>\n
    4. Test tube holder<\/span><\/li>\n
    5. Bunsen burner or hot water bath<\/span><\/li>\n<\/ol>\n

      Chemicals<\/strong><\/em><\/span><\/p>\n

        \n
      1. Molisch Reagent (\u03b1-naphthol in ethanol)<\/span><\/li>\n
      2. Concentrated sulfuric acid (H\u2082SO\u2084)<\/span><\/li>\n
      3. Fehlind Sol A (Copper(II) sulfate solution) & B (Alkaline solution of potassium sodium tartrate (Rochelle salt) in sodium hydroxide)<\/span><\/li>\n
      4. Benedict Reagent ((contains copper(II) sulfate, sodium carbonate, and sodium citrate))<\/span><\/li>\n
      5. Sample (glucose, fructose, sucrose)<\/span><\/li>\n
      6. Distilled water<\/span><\/li>\n<\/ol>\n

        Theory:<\/strong><\/span><\/p>\n

        Carbohydrates are organic compounds containing carbon, hydrogen, and oxygen.\u00a0They include simple sugars (monosaccharides), disaccharides, and polysaccharides. Molisch\u2019s test is commonly used as a general test. This test is based on the dehydration of carbohydrates by concentrated sulfuric acid to form furfural or hydroxymethylfurfural, which then react with \u03b1-naphthol (Molisch\u2019s reagent) to produce a purple or violet ring at the interface of the acid and the aqueous layer.<\/span><\/p>\n

        \n
        \n
        In Fehling’s Test: Reducing sugars react with the copper ions in Fehling’s reagent to form copper(I) oxide (Cu2O), which precipitates out as a brick-red solid which<\/span>\u00a0indicates the presence of reducing sugars.<\/span>\u00a0<\/span><\/span><\/span><\/div>\n
        \n
        \n
        \n
        In Benedict’s Test: \u00a0<\/span>Similar to Fehling’s test, reducing sugars reduce the copper(II) ions in Benedict’s reagent to copper(I) oxide, which precipitates out.<\/span>\u00a0<\/span>The reagent changes color, ranging from green, yellow, orange, or red, depending on the concentration of reducing sugars.\u00a0<\/span><\/span><\/span><\/span><\/div>\n
        \u00a0<\/span><\/div>\n
        Procedure<\/strong><\/span><\/div>\n
        Molisch Test<\/strong><\/span><\/div>\n
        \n
          \n
        1. Take 2 mL of the aqueous carbohydrate solution in a clean test tube.<\/span><\/li>\n
        2. Add 2\u20133 ml of Molisch\u2019s reagent (\u03b1-naphthol in ethanol) to the solution.<\/span><\/li>\n
        3. Carefully add 1\u20132 drops of concentrated sulfuric acid along the sides of the test tube using a dropper or pipette. Do not mix. Allow the acid to settle at the bottom.<\/span><\/li>\n
        4. Observe the formation of a violet or purple ring at the junction of the two liquids.<\/span><\/li>\n<\/ol>\n

          D-glucose+con H2SO4——>5 Hydroxy methyl furfural—>+alpha nephthol—>purple\/violet ring<\/strong><\/p>\n

          \"\"<\/p>\n

          Fehling’s Test:<\/strong><\/span><\/p>\n

            \n
          1. Mix 1 mL of Fehling\u2019s solution A and 1 mL of Fehling\u2019s solution B in a test tube to prepare fresh Fehling\u2019s reagent.<\/span><\/li>\n
          2. Add 2 mL of the carbohydrate solution (or a few crystals of the solid sample dissolved in water) to the test tube.<\/span><\/li>\n
          3. Gently heat the mixture in a boiling water bath for 2\u20135 minutes or directly over a low flame with a test tube holder.<\/span><\/li>\n
          4. Observe any color change or precipitate (red) formation.<\/span><\/li>\n<\/ol>\n

            \"\"<\/p>\n

            Benedict Test<\/strong><\/span><\/p>\n

              \n
            1. Take 2 mL of the carbohydrate solution in a clean test tube.<\/span><\/li>\n
            2. Add 2 mL of Benedict\u2019s reagent to the test tube.<\/span><\/li>\n
            3. Mix well and heat the solution in a boiling water bath for 3\u20135 minutes, or gently over a flame.<\/span><\/li>\n
            4. Observe the color change or precipitate formation.<\/span><\/li>\n
            5. \n

              The degree of color change can give a rough estimate of sugar concentration:<\/span><\/p>\n

                \n
              • \n

                Blue<\/strong> (no change): No reducing sugar<\/span><\/p>\n<\/li>\n

              • \n

                Green<\/strong>: Trace amount<\/span><\/p>\n<\/li>\n

              • \n

                Yellow<\/strong>: Low concentration<\/span><\/p>\n<\/li>\n

              • \n

                Orange<\/strong>: Moderate concentration<\/span><\/p>\n<\/li>\n

              • \n

                Brick-red<\/strong>: High concentration<\/span><\/p>\n<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n

                \"\"<\/p>\n

                Observation\u00a0<\/strong><\/p>\n

                Molisch Test: ………………………….color is found<\/span><\/p>\n

                Fehling Test: ………………………….color is found<\/span><\/p>\n

                Benedict Test:\u00a0 ………………………….color is found<\/span><\/p>\n

                Result: Qualitative analysis of organic compound for detection of carbohydrate was done successfully.<\/strong><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

                Experiment No. 5 Objective Qualitative Analysis of unknown organic compound for detection of carbohydrate References: Dr. Jain K.S., Dr. Miniyar P.B., A practical book of Pharmaceutical organic chemistry , Nirali publication, edition 4th, page No. 1.31-1.33 Vogel Arthere, Elementary practical organic chemistry, 2nd edition, 1966, published by CBS publisher, page No. 89 Requirement Glasswares and […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":"","_glsr_average":0,"_glsr_ranking":0,"_glsr_reviews":0},"categories":[1],"tags":[],"_links":{"self":[{"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/posts\/1576"}],"collection":[{"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/comments?post=1576"}],"version-history":[{"count":9,"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/posts\/1576\/revisions"}],"predecessor-version":[{"id":1603,"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/posts\/1576\/revisions\/1603"}],"wp:attachment":[{"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/media?parent=1576"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/categories?post=1576"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/medpharma12.com\/index.php\/wp-json\/wp\/v2\/tags?post=1576"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}