Answer
a) Carboxylic acid
b) Ester
c) Acyl chloride / acid chloride
d) Amide
Work Step by Step
a) Identify the functional group here. $-COOH$ is present here which is functional group of carboxylic acid. Therefore, it is an example of carboxylic acid.
b) Identify the functional group $-COO-R$. This is ester functional group. So, the compound is an ester.
c) functional group here is $-COCl$ which is acyl chloride functional group. So, this molecule belongs to acyl chloride.
d) Functional group here is $-CONH_{2}$ which is an amide group. So, the compound is an amide.
