What happens when : (a) Propanenitrile is treated with phenyl magnesium bromide followed by hydrolysis ? (b) p-fluorotoluene is treated with $ ext{CrO}_3$ in the presence of acetic anhydride followed by hydrolysis with aqueous acid. (c) Phthalic acid is treated with $ ext{NH}_3$ followed by heating ? Write chemical reactions in support of your answer.