This document describes using Molisch's test to test for the presence of carbohydrates in a sample. It provides the aim, materials needed, and procedure for the test. The procedure involves adding a sample to Molisch's reagent, which is alpha-naphthol in an alcoholic solution, and then carefully layering concentrated sulfuric acid on the side of the test tube. If a purple ring forms at the interface of the two layers, then carbohydrates are present in the sample. Glucose, lactose, sucrose, and starch solutions were all observed to produce a positive purple ring, confirming the presence of carbohydrates.

1. AIM:-TO TEST THE PRESENCE OF CARBOHYDRATES
IN THE GIVEN SAMPLE USING MOLISCH’S TEST
Lecture by:- Dr. Mohan
Kumar
Assistant professor
Gyan Joyti Collage of Pharmacy, Hazaribag
Email:- mohank087@gmail.com

2. EXPERIMENT:-1
AIM:-TO TEST THE PRESENCE OF CARBOHYDRATES IN
THE GIVEN SAMPLE USING MOLISCH’S TEST.
Theory:
The word carbohydrate is formed from the words carbon
and hydrogen. Carbohydrates are combinations of the
chemical elements carbon and hydrogen plus oxygen. In
the natural world, carbohydrates are the most common
chemical compounds used for food.
Molisch’s test is a general test for carbohydrates. This
test is given by almost all of the carbohydrates. In this
test concentrated sulfuric acid converts the given
carbohydrate into furfural or its derivatives, which react
with α-naphthol to form a purple coloured product.

3. MATERIALS REQUIRED:
 Molisch’s reagent
 Glucose solution
 Concentrated sulfuric acid
 Test tubes
 Measuring cylinder
 Test tube holder
 Test tube stand
 Dropper
 Stirrer
 Pipette
 Distilled water

4. Procedure:
 First prepared the Molisch’s reagent by adding α-naphthol in
10% alcoholic solution.
 Take 2ml of given sample solution in a clean test tube.
 Add 2-3 drops of Molisch reagent slowly.
 Now add concentrated sulfuric acid along the sides of the
test tube.
 The acid layer forms a layer at the bottom.
 If there is formation of violet ring then the presence of
carbohydrate is confirmed.

5. Take sample of sugar
solution
Add Molisch’s
reagent
Add
conc.H2SO4
Formation
of violet
ring

6. OBSERVATIONS:
Test Glucose Lactose Sucrose Starch
Molisch’s
test
Purple ring Purple ring Purple ring Purple ring

7. RESULTS AND DISCUSSIONS:
 The given organic compound is a reducing sugar.
Precautions:
 Handle the acids like concentrated sulfuric acid with care.
 Always use droppers to take reagents from the reagent
bottles.