Give the type of isomerism exhibited by each of the following pairs:
a. Acetic acid and methyl formate
b. `o-` Nitrophenol and `m-` nitrophenol
c. `n-` Butance and isobutance
d. Maleic and fumaric acid
e. Benzyl alcohol and `o-` methyl phenol
f. Propionic acid and methyl acetate
g. `n-`Butyl alcohol and diethyl ether
h. `1,1-` Dibromoethane and `1,2-` dibromoethane