Question

Note: Consider the following four compounds for answering the question

$I$

$II$


$III$
$IV$
Which of the following pairs are position isomers?

• A. I and II
• B. II and IV
• C. III and IV
• D. II and III

Answer 1

The correct option is D

II and III

Positional isomers

Positional isomers have the same principal chain but differ in position of substituents or functional group.

In the molecule $\left(II\right),$ ketone group is at $2nd$ position but in molecule $\left(III\right),$ ketone is at $3rd$ position.

So, positional isomers are $II$ and $III.$

Hence, the correct choice is $\left(B\right).$