Number of primary structural alcoholic isomers possible for ${\mathrm{C}}_5{\mathrm{H}}_{11}\mathrm{OH}$

Given: It is given to find the Number of primary structural alcoholic isomers possible for $C_5{H}_{11}OH$.

Concept: Structural isomers

Explanation: The number of possible primary structural alcoholic isomers possible for $C_5{H}_{11}OH$ are as follows. 

Therefore, the number of possible  primary structural alcoholic isomers possible for $C_5{H}_{11}OH$ are  4.