Question

7. Write an equation for the reaction of the potassium soap with hydrochloric acid, showing the structures of reactants and products.

8. What is the solid precipitate that was formed (in Question 7)? Did the product show sudsing action? Explain the behavior.

Answer 1

The molecule of soap constitutes sodium or potassium salts of long chain carboxylic acids.

Hence it has two ends :one is hydrophobic(water repellent: long chain carboxylic acid part) and the other is hydrophilic.(water loving means disolves in water: alkaline part that is Na+ or K+)

Soap that is derived from palm oil is sodium palmate (CH3(CH2)14CO2Na) or potassium palmate(CH3(CH2)14CO2K.

Usually sodium soaps are used for washing clothes and potassium soaps are used for bathing.

Most of the dirt is oily in nature and oil does not dissolve in water it dissolves in organic solvents.

7) Reaction of the potassium soap with hydrochloric acid:

CH3(CH2)14COOK + HCl      --------------->    CH3(CH2)14COOH + KCl

potassium palmate                                                  palmic acid               

8) The solid precipitate formed is the dirt present on the body, which forms a micelle with the hydrophobic part (hydrocarbon part) of the soap.

Here colloidal size of the dirt is converted into the suspension size by forming the micelles(clusters) by the soap.

The hydrophobic end of the soap forms a cluster around the dirt and the hydrophilic end will be facing outside the cluster.

When it is washed with water the dirt will be removedn in the form of (micelles) big molecules(clusters.)

SUDSING action means forming lather.The product shows this sudsing action.