Identify the reaction

This question is from compounds containing nitrogen, and the options suggest products obtainable from a nitrile or related nitrogen derivative.

The standard reaction typically asked here is the Stephen reduction, in which a nitrile $R-C\equiv N$ is reduced under controlled conditions to give an aldehyde after hydrolysis.

Relevant transformation

The sequence is:

$R-C\equiv N \xrightarrow[\text{HCl}]{\text{SnCl}_2} R-CH=NH \cdot HCl \xrightarrow{H_2O} R-CHO$

So, nitrile is converted into an aldehyde.

Check the options

• A: $RCOOH$

  This is obtained by hydrolysis of nitrile under acidic/basic conditions, not by Stephen reduction.

• B: $RCONH_2$

  This is the amide, usually formed by partial hydrolysis of nitrile, not the major product here.

• C: $RCHO$

  This is the aldehyde formed in Stephen reaction. Correct.

• D: $RCH_2NH_2$

  This is a primary amine, obtained by catalytic reduction or $LiAlH_4$ reduction of nitrile, not here.

Conclusion

Therefore, the major product is:

$\boxed{RCHO}$

Comparison with stored answer

Stored correct answer: C

Our derived answer: C

Hence, they agree.