Question

but-3-enoic acid react in presence of h2/ni​

Answer 1

Next, here's a reactivity order:

First, the groups which are easily reduced:

acid halide>R−C≡C−R>R−C=C−R>R−CHO>ketone>R−CN>R−NO2>…

Then the groups that are reduced only with difficulty:

…>R−X>benzene>R−COOH>amide>ester>acid anhydride