Alkanes

30. ​​ M/J​​ 2015/P12/Q36,​​ M/J​​ 2015/P11/Q35

When cracked, one mole of a compound, X, produces one mole of propene and one mole of​​ hydrogen.

X → C3H6​​ + H2

What type of compound is X?

A​​ ​​ an alcohol

B​​ ​​ an alkane

C​​ ​​ an alkene

D​​ ​​ a carboxylic acid

 

Answer: ​​ B

Explaination

Cracking converts saturated hydrocarbon into unsaturated hydrocarbon (alkene).​​ 

For example, cracking large HC hexane, it becomes smaller alkene molecule. The products obtained in cracking are alkene always and H2​​ gas may also be produced.

The complete equation will be

C3H8​​ → C3H6​​ + H2