(a) CH3CH2CH2Br+KOH→CH3CH=CH2+KBr+H2O→Elimination reaction Formation of π-bond and conversion of saturated compound into unsaturated compound by the removal of groups or atoms is known as Elimination reaction
Replacement of one group by other group known as Substitution Reaction
Conversion of unsaturated compound into saturated compound by the addition of groups or atoms is called as addition reaction.