CBSE Class 10 Answered

Alcohol:

To test an alcohol, you can use sodium metal test.

Add a very small piece of sodium metal to ethanol. A colourless gas will be liberated. Bring a lighted match stick near the mouth of the test tube. The match stick burns with a pop sound.

2 CH₃CH₂OH + 2 Na 2 CH₃CH₂ONa + H₂

Ethanoic acid:

Sodium bicarbonate test:

Add solid sodium bicarbonate to a carboxylic acid, brisk effervescence of CO₂ is produced.

2 CH₃COOH + NaHCO₃ 2 CH₃COONa + H₂O + CO₂

Soap solution:

Add a little water to soap solution and shake. Froth will be formed. Dip a red litmus paper in the soap solution. It will turn blue. Also, a soap solution will be soapy to touch.

So, when you are given three test tubes, first perform sodium bicarbonate test in all the three test tubes. The one that gives a positive test will be ethaoic acid. Then to the remaining two, perform sodium metal test. The one that gives positive test is alcohol. The last one is soap solution. Perform the test for soap for this test tube to confirm.