Question

Petroleum is a mixture of hydrocarbons and boiling point of hydrocarbon increases with

1. increase in the number of hydrogen atoms
2. increase in the number of carbon atoms
3. decrease in the number of carbon atoms
4. Can't be predicted

Answer 1

Answer: 2. Increase in the number of carbon atoms.

Explanation: This is because as a result of an increase in number of carbon atoms (molecular size), the London Dispersion Forces also increases, making it difficult for the molecules to separate because they are strongly attracted to each other,hence resulting in a higher boiling point.

Answer 2

Petroleum is a mixture of hydrocarbons. Each hydrocarbon consists of carbon and hydrogen atoms. A hydrocarbon contains carbon chain and its boiling and melting points increase with increase in length of the carbon chain. The length of the carbon chain increases with increase in the number of carbon atoms forming bonds. Therefore, the boiling point of hydrocarbon increases with increase in the number of carbon atoms.

(Answer) (2) increase in the number of carbon atoms.