Question

Which of the following functional groups are reduced by hydrogen in presence of $Ni/H_2$ catalyst?

• A. $>C=C<$
• B. $-C\equiv C-$
• C. $-CN$
• D. $-CHO$

Answer 1

Answer: (A), (B), (C), (D)

The correct options are
A $>C=C<$
B $-C\equiv C-$
C $-CN$
D $-CHO$

All the above mentioned functional groups can be reduced by $Ni/H_2$ catalyst.

For example-

Reduction of acetylene to Ethylene is given as-

$CH$ $\equiv$ $CH$ $+$ $H_2$ $\stackrel{Ni}{⟶}$ $C{H}_2=C{H}_2$

Reduction of Ethylene to Ethane is given as-

$C{H}_2=C{H}_2$ $+$ $H_2$ $\stackrel{Ni}{⟶}$ $C{H}_3-C{H}_3$

Reduction of Aldehyde group to Alcohol is given as-

$C{H}_3-CHO$ $+$ $H_2$ $\stackrel{Ni}{⟶}$ $C{H}_3-C{H}_2-OH$

Reduction of Nitrile group to Amine is given as-

$C{H}_3-C$$\equiv$$N$ $+$ $H_2$ $\stackrel{Ni}{⟶}$ $C{H}_3-C{H}_2-N{H}_2$

Thus options A, B, C and D all can be reduced by Hydrogen in presence of $Ni$ catalysts.

But, the Nitrile group, that is $R-C$$\equiv$$N$ can be reduced less easily by Hydrogen in presence of Nickel catalysts. All the other functional groups are easily reduced.