Acetonitrile on reduction gives:A. ethanamineB. propanamineC. methenamineD. None of the above

To solve the question, we first need to understand the chemical nature of acetonitrile and the reduction process involved.

Acetonitrile (chemical formula: CH₃CN) is a nitrile, which contains a cyano group (-C≡N) attached to a methyl group (CH₃-). When acetonitrile undergoes reduction, the cyano group can be converted into an amine group (-NH₂).

Reduction of Acetonitrile
The reduction of acetonitrile typically involves the following reactions:

Reduction with Hydrogen and a Catalyst:

When acetonitrile is reduced using hydrogen gas in the presence of a catalyst (such as palladium or nickel), it can convert to ethylamine (C₂H₅NH₂).
Reduction with Lithium Aluminium Hydride (LiAlH₄):

Acetonitrile can also be reduced by lithium aluminium hydride, yielding ethylamine.
Analyzing the Answer Choices
Now, let's analyze the provided options:

A. Ethanamine (C₂H₅NH₂): This is the product formed when acetonitrile is reduced.
B. Propanamine (C₃H₇NH₂): This is not produced from acetonitrile.
C. Methenamine (C₆H₁₄N₄): This is not a direct product of acetonitrile reduction.
D. None of the above: This would be incorrect since ethanamine is formed.

Conclusion
The correct answer is A. ethanamine.

In summary, when acetonitrile is reduced, it primarily forms ethanamine (ethylamine) as the product.