Write structures of compounds A,B and C in each of the following reaction:
(i) C6H5‌Br‌ ‌

Mg∕‌ dry ether ‌

─────▸

‌A‌ ‌

(a) CO2(g)

─────▸

‌ (b) ‌H3O+

B

PCl3

───▸

C
(ii) CH3‌CN‌ ‌

(a)SnCl2∕HCl

─────▸

‌ (b) ‌H3O+

‌A‌ ‌

‌ dil. ‌NaOH

─────▸

‌ B ‌

∆

──▸

‌ C ‌
OR
Do the following conversions in not more than two steps:
(i) Benzoic acid to benzaldehyde
(ii) Ethyl benzene to benzoic acid
(iii) Propanone to propene