Question

10. A hydrocarbon molecule contains 4 hydrogen atoms. Give its molecular formula, if it is an: (i) alkane (ii) alkene (iii) alkyne.

Answer 1

Answer:

alkane- CH4 ; alkene- C2H4 ; alkyne- C3H4

Explanation:

Answer 2

Given: A hydrocarbon molecule contains 4 hydrogen atoms.

To find: We have to find the molecular formula of (i) alkane (ii) alkene (iii) alkyne.

Solution:

• The general formula of an alkane is $C_nH_{2n+2}$.

The number of hydrogen atoms is 4.

So, 2n+2=4

n=1

Thus the formula of the alkane is $CH_4$.

• The general formula of an alkene is $C_nH_{2n}$.

The number of hydrogen atoms is 4.

So, 2n=4

n=2

Thus the formula of the alkene is $C_2H_4$.

• The general formula of an alkyne is $C_nH_{2n-2}$.

The number of hydrogen atoms is 4.

So, 2n-2=4

n=3

Thus the formula of the alkyne is $C_3H_4$.