Question

What is the number of carbon atoms in the longest continuous chain which is a 2-methyl alkane with the molecular mass of 72.

Answer 1

Since it is an alkane $\left(C_n{H}_{2n+2}\right)$,

$\therefore 12n+2n+2=72$
$⟹n=5$
Since there is one carbon substituent, therefore number of carbon in longest chain is 4.