(a) Gabriel synthesis ⟶ (iii) Primary amines 
Pthalimide is alkylated with primary or unbranched secondary alkyl halides or sulphonate. The product thus obtained is hydrolysed to give primary amines. 



Treatment of toluene with chromyl chloride in an inert solvent like CS2 or CCl4 forms an insoluble complex C6H5CH(OCrCl2OH)2 which further on hydrolysis produces benzaldehyde.