Question

(a) What is meant by a substitution reaction? Give an example (with equation) of the substitution reaction of an alkane.
(b) How is soap made? Write a word equation involved in soap making.

Answer 1

Answer:

(a) A reaction in which one atom of a molecule is replaced by another atom (or group of atoms) is called a substitution reaction.

e.g. CH4+Cl2-CH3Cl+HCl.

Answer 2

Soap Formation is called Saponification

Explanation:

a.) Substitution reaction is a characteristic of saturated hydrocarbons. The reaction in which one (or more) hydrogen atoms of a hydrocarbon are replaced by some other atoms (like chlorine), is called a substitution reaction.

Example: Methane ($CH_4$) reacts with chlorine in the presence of sunlight to form chloro-methane and hydrogen chloride.

$CH_4 + Cl_2$ -Sunlight $CH_3Cl + HCl$

b.) Soaps are made from animal fat or vegetable oils by heating it with sodium hydroxide.

$C_2H_5OH + CH_3COOH = CH_3COOC_2H_5 + H_2O$

$CH_3COOC_2H_5 + NaOH = C_2H_5OH + CH_3COONa$

The Process is called Saponification.

* Refer the attached figures for reactions