Question

What kind test and what kind results you will have for these compounds listed below:

Anise, amine, primary alcohol, Alkenes, ketones, aldehydes, carboxylic acid.

Answer 1

Amine

Carbylamines Test:

Take a small quantity of solid KOH in a clean dry test tube and add about 2 ml of ethanol. Warm the test tube until the pellets dissolve. To this add a few drops of chloroform and small amount of the given compound and warm gently.

Observation:If an offensive smell is produced amine is present.

Primary alcohol

Lucas Test:

Take about 1 ml of dry alcohol in a clean dry test tube and add 8-10 drops of Lucas reagent. Shake the mixture well

Observation: If cloudiness appears only upon heating, primary alcohol is present.

Alkene

Bromine water test:

Bromine water is used to tell the difference between an alkane and an alkene. An alkene will turn orange-brown bromine water colourless as it reacts with the double bond and compound becomes saturated.

ketones

2,4-Dintrophenyl hydrazine Test:

Take a small quantity of the given compound in a clean dry test tube, add rectified spirit until the compound just dissolves. Now add few drops of 2, 4-dinitrophenyl hydrazine solution. Cork the test tube, shake the mixture and allow it to stand for 5 minutes.

Observation:If yellow or orange precipitate is formed carbonyl group is present.

aldehydes

Tollen’s Test (Silver mirror test):

Take about 1 ml of silver nitrate solution in a clean test tube and add 2-3 ml of dilute NaOH solution. A brown precipitate of silver oxide forms. Now add dilute ammonia solution dropwise until the brown precipitate of silver oxide just dissolves. To this add 3-4 drops of the given liquid (or 0.1 g if solid) and warm the test tube on a water bath for about 5 minutes.

Observation:Shining silver mirror is formed, aldehyde is present.

carboxylic acid:

Sodium Hydrogen Carbonate Test:

Take 1 ml of the given organic compound in a test tube and add a pinch of sodium bicarbonate to it.

Observation :If brisk effervescence is observed, carboxylic group is present.