Question

Which of the following statement(s) is/are not true according to the given structures?

• A. (i), (ii), (iii) are chain isomers
• B. (v) and (vi) are chain isomers
• C. (i), (ii) and (v) are chain isomers
• D. (ii) and (vi) are chain isomers

Answer 1

Answer: (C), (D)

The correct options are
C (i), (ii) and (v) are chain isomers
D (ii) and (vi) are chain isomers

In chain isomerism, the compounds have the same molecular formula but different properties due to different arrangements of carbon chain present in them. Thus, the type of chain is branched or un-branched.

The molecular formula of $\left(i\right),\left(ii\right),\left(iii\right)$ are $C_7{H}_{12}O$ and (iv) is $C_6{H}_{10}O$ and (v),(vi) are $C_7{H}_{13}O$.

Thus the statement (C), "(i), (ii) and (v) are chain isomers" is not true.
(i) and (ii) are cyclic compounds whereas (v) is an open-chain compound. The compound (v) contains 2 H atoms more than compounds (i) and (ii). Hence, the molecular formula of compound (v) is different from the molecular formula of compounds (i) and (ii).

Also, the statement (D), " (ii) and (vi) are chain isomers" is also not true for the same reason.