Question

Molecular weight of an alkane was found to be $142$. Suggest its molecular formula.

Answer 1

Given:

Molecular weight of an alkane= $142$

Molecular formula for alkane= $C_n{H}_{2n+2}$

i.e, $12n+2n+2=142$

$\Rightarrow 14n=140$

$\Rightarrow n=10$

$\therefore$ Molecular formula is $C_{10}{H}_{22}$