Experiment Name: Conversion of water-insoluble Salicylic acid into water Sodium Salicylate.

Principle:

Water is a polar molecule. It dissolved only polar solid. In pharmaceuticals, a Polarity increment may be required during several operations like liquid dosage form preparation. The increment is done by the addition of polar salt or base with various non-polar substances. Increase the solubility of the solution with water.

Salicylic acid topical is used in the treatment of acne, dandruff, seborrhea, or psoriasis, and to remove warts. Naturally, cucumber, broccoli, cauliflower, corn, radish, sweet potato, and fennel contain Salicylates.

Reaction:

Fig. 2.1: Reaction between Salicylic acid and Sodium Carbonate.

Reagent:

§  Salicylic acid

§  Sodium carbonate

§  Distilled water

Apparatus:

§   01.Test tube

§   02.Dropper

Procedure:

01. Take a small amount of salicylic acid powder (< 0.5 gm).

02. Add a small amount of H₂O (approximately 1 ml) and shake

03. Observe that the powder is not Dissolving.

04. Now added a small amount of NaCO₃ and shake well.

05. Observed that it dissolves the Salicylic acid.

Observation:

Salicylic acid completely dissolved in the water due to the formation of Di-sodium Salicylate acid.

Result:

Salicylic acid-insoluble in the water but di-sodium salicylate soluble in the water

Comment:

Salicylic acid turned into di-sodium salicylate which was soluble in water

Precaution: 

§  Have to wear laboratory apron, hand gloves, masks, shoes & goggles.

§  Have to be very careful during the experiment.

§  Wash apparatus with clean water.