Question

Short Notes
(a) Oxidation Reaction: 
(b) Substitution Reaction: 
(c) Roasting:

Answer 1

(a) Oxidation Reaction:
A process involving gain of oxygen, loss of hydrogen, or loss of electrons. Example: \(\mathrm{2\,Mg + O_2 \rightarrow 2\,MgO}\).

(b) Substitution Reaction: 
One atom or group in a molecule is replaced by another atom/group. Typical in saturated hydrocarbons: \(\mathrm{CH_4 + Cl_2 \xrightarrow{hv} CH_3Cl + HCl}\).

(c) Roasting: 
Heating of sulphide ores in the presence of excess oxygen to convert them into oxides and to remove volatile impurities. Example: \(\mathrm{2\,ZnS + 3\,O_2 \rightarrow 2\,ZnO + 2\,SO_2}\).