Question

In the halogenation reaction shown, ethane and chlorine gas yield chloroethane and hydrogen chloride. How do the properties of chloroethane compare to those of ethane?

Chloroethane is denser and has a lower boiling point
Chloroethane is denser and has a higher boiling point
Chloroethane is less dense and has a lower boiling point.
Chloroethane is less dense and has a higher boiling point.

Answer 1

Chloroethane is denser and has a higher boiling point

Step-by-step explanation:

The density of a gas depends directly on the molar mass of the gas. This means that as the molar mass increases, density increases and vice versa.

Having said that, we can easily see that the molar mass of chloroethane (64.51 g/mol) is greater than the molar mass of ethane (30.07 g/mol). Hence we expect that chloroethane is denser than ethane as established above.

In the absence of other strong intermolecular forces, the higher the molecular mass of a substance the greater its boiling point. Thus the boiling point of chloroethane is higher than that of Ethane since they both have weak Van der Waals forces holding their molecules together in the gaseous state.