Question

An organic compound whose molecular formula C4H10O reacts with PCl5

forms a compound (A) which also reacts with KCN to form another organic

compound (B) that given an organic acid (C) upon hydrolysis. Write all chemical

equation for the reaction involved.​

Answer 1

Compound A is butyl chloride (C₄H₉Cl).

Compound B is pentanenitrile (C₄H₉CN).

Compound C is pentanamide (C₄H₉CONH₂).

• A compound with a molecular formula of C₄H₁₀O is given.

We know that alcohols have a general molecular formula of CₙH₂ₙ₊₁OH. Therefore, the molecular formula of C₄H₁₀O can also be written as C₄H₉OH (butanol).

• Now, the reaction of butanol and PCl5 proceeds as follows :

C₄H₉OH + PCl₅  → C₄H₉Cl (A) + HCl + POCl₃

∴   Compound A is butyl chloride.

• C₄H₉Cl + KCN →  C₄H₉CN (B) + KCl

∴   Compound B is butyl cyanide or pentanenitrile.

• Further, hydrolysis of pentanenitrile gives pentanamide.

C₄H₉CN + H₂O → C₄H₉CONH₂ (C)

∴ Compound C is pentanamide.