Question

(a) What happens when methane reacts with chlorine? Give equation of the reaction which takes place.
(b) What is hydrogenation? What is its industrial application?
(c) Give any two differences between soaps and detergents.

Answer 1

(a) When methane reacts with chlorine, substitution reaction takes place. Methane reacts with chlorine in the presence of sunlight to form chloromethane and hydrogen chloride. In this reaction, chlorine substitutes hydrogen; therefore, this reaction is also known as chlorination.

The chemical equation for this reaction is: ${\mathrm{CH}}_4+{\mathrm{Cl}}_2\stackrel{}{\to {\mathrm{CH}}_3\mathrm{Cl}+\mathrm{HCl}}$

(b) Hydrogenation is the process of adding hydrogen to an unsaturated hydrocarbon for obtaining a saturated hydrocarbon in the presence of a catalyst.

Chemical reaction: ${\mathrm{CR}}_2={\mathrm{CR}}_2+{\mathrm{H}}_2\underset{\mathrm{Heat}}{\overset{\mathrm{Ni}\mathrm{catalyst}}{\to }}{\mathrm{HCR}}_2-{\mathrm{HCR}}_2$
Industrial application: The hydrogenation process is used to make ghee (saturated fat) from vegetable oils (unsaturated fat).

(c)

Sl.No	Soaps	Detergents
1.	Soaps are salts of sodium or potassium of the long chain carboxylic acids. The ionic group present in a soap is COO-Na+.​	Detergents are salts of sodium of long chain benzene, sulphonic acids or long chain alkyl hydrogensulphates. The ionic group present in a detergent is SO3-Na+.​
2.	Soaps have weak cleansing action compared to detergents.	The cleansing action of detergents is stronger to that of soaps.