MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

The given reactant is pent-3-enenitrile, which has the structure CH _3- CH = CH - CH _2- CN . Diisobutylaluminium hydride (DIBAL-H), represented as AlH(i-Bu) _2, is a selective reducing agent. It reduces nitriles to imines at low temperatures, which upon subsequent acidic hydrolysis ( H _3 O ^+) yield aldehydes. DIBAL-H does not reduce isolated carbon-carbon double bonds. The reaction proceeds as follows: CH _3- CH = CH - CH _2- C N AlH(i-Bu) _2 CH _3- CH = CH - CH _2- CH = N - Al(i-Bu) _2 CH _3- CH = CH - CH _2- CH = N - Al(i-Bu) _2 H _3 O ^+ CH _3- CH = CH - CH _2- CHO The final product is pent-3-enal. Answer: Pent - 3 - enal