Question

suggest molecular formula for an alkane having molecular mass 142​

Answer 1

The Alkane is Decane.

Molecular Formula will be

$\boxed{C_{10}H_{22}}$

$\rule{200}{2}$

Mass of Carbon = 12 units

Mass of Hydrogen = 1 units

General formula of Alkanes is :-

$\boxed{C_{n}H_{2n+2}}$

$\rule{200}{2}$

Atomic mass of Alkane with n carbon atoms will be as follows :-

$12n + 2n + 2$

$\rule{200}{2}$

Now,

Atomic mass of given alkane is 142 units.

So,

$14n + 2 = 142 \\ \\ \\ 14n = 142 - 2 = 140 \\ \\ \\ n = \frac{140}{14} = 10$

Thus,

The alkane has 10 carbon atoms and 22 Hydrogen Atoms.

Thus,

The compound is Decane.