Question

Which of the following cannot be an isomer of pentane?

• A. n-pentane
• B. 2,2 dimethyl propane
• C. 3,3 dimethyl butane
• D. 2- methyl butane

Answer 1

The correct option is C

3,3 dimethyl butane

Pentane is a 5 carbon compound with formula $C_5{H}_{1}2$. The possible structures of its isomers are as shown. Its names are as follows:

n-pentane, 2,2 dimethylpropane, 2- methyl butane. The third and fourth structures are the same.

3,3 dimethyl butane is a 6 carbon structure so it cannot be an isomer for pentane.