Question

merits and demerits of soap and detergent​

Answer 1

soap creates scum in hard water but detergent do not

Answer 2

(i) Soap is cheaper and readily available.
(ii) It works well for cleaning of clothes with soft water (water which does not contain Ca तथा Mg )
(iii) Soaps are 100% biodegradable, i.e., decomposed by micro-organisms present in sewage, therefore, they do not create water pollution.
94. Disadvantages of Soap :
(i) It does not work well with hard water containing Ca or Mg . It reacts with Ca and Mg to form white precipitate which is called scum and soap goes waste. The reaction which takes place is a follows.
Thus, soap solution forms less lather with hard water.
(ii) Soap is not suitable for washing woolen garments because it is basic in nature and woolen garments have acidic dyes.
(iii) Soap are less effective in saline water and acidic wate Detergents
95. Detergents : Detergents are sodium or potassium salts of sulphonic acids of hydrocarbons of alkene type. They have –SO H group, i.e., sulphonic acid group.
Examples :
(i) Sodium lauryl sulphate
(ii) Sodium dodecylbenzenesulphonate
96. Advantages of Detergents over soaps :
(i) Detergents work well even with hard water but soaps do not.
(ii) Detergents may be used in saline or acidic water
(iii) Detergents are more easily soluble in water than soaps.
(iv) Detergents can be used for washing woolen garments whereas soaps cannot be used.
(v) Detergents having linear hydrocarbon chain are biodegradable.
97. Disadvantages of Detergents over Soaps :
(i) Synthetic detergents having branched hydrocarbon chain are not fully biodegradable, i.e., they are not decomposed by micro-organisms in sewage and create water pollution.
(ii) They are more expensive than soaps. Let us take up differences between soaps and detergents.