Question

How is detergent different from soap? These days detergents are preferred to soaps. Give reasons.

Answer 1

Step 1:

The long-chain carboxylic acids containing Sodium $\left(\mathrm{Na}\right)$ or Potassium $\left(\mathrm{K}\right)$ salts are called soaps.

The long-chain carboxylic acids containing Ammonium $\left({{\mathrm{NH}}_4}^{+}\right)$or Sulphonate $\left({{\mathrm{RSO}}_3}^{-}\right)$ salts are called detergents.

Step 2:

Natural ingredients such as vegetable oil or palm oil are used to make soaps or sometimes soaps are derived from animal fats.

Detergents are man-made or synthetic derivatives.

Step 3:

Detergents are preferred over soaps due to the following reasons:

(i) Detergents are preferred to soaps because of their cleansing effect in hard or saline water.

(ii) Detergents dissolve in water easily but soaps take time to get dissolve in water. So detergents are superior to soaps.

(iii) Detergents produce foam in soft and hard water but soap does not form foam in hard water.

(iv) The Sulfonate group present in detergents does not attach itself to the Calcium $\left(\mathrm{Ca}\right)$ and Magnesium $\left(\mathrm{Mg}\right)$ ions present in hard Water to form insoluble precipitates.

(v) Detergents do not form scum so detergents are preferred to soaps these days.