Question

The boiling point of bromoethane is higher than that of chloroethane. Why?

Answer 1

Hint: Boiling point is that temperature at which the liquid begins to boil and boiling point increases with increase in the surface area of the molecule, atomic mass of the molecule but decreases with branching. Now with the help of this you can easily answer the given statement accordingly.

Complete answer:
First let's discuss chloroethane and bromoethane. Ethane is a two-carbon compound which comes under the category of the alkanes and consists of a -C-C single bond. When one hydrogen of ethane is replaced with the chlorine, then it is called as chloroethane and when the bromine is attached in place of the chlorine then it is called as bromoethane.
Now considering the statement;-
Boiling point is that temperature at which the liquid begins to boil or simply we can say that at which the liquid changes into the vapor phase.
There are certain rules for boiling point which should be kept in mind while arranging the compounds in the increasing or decreasing order of their boiling points. These are as follows:-
1. boiling point increases with increase in the surface area of the molecule.
2. As the molecular mass of the compound increases, boiling point also increases.
3. Boiling point decreases with the branching because surface areas decrease with branching.
 So, the atomic mass of Bromoethane is 108.97 and chloroethane is 64.51 and thus, bromoethane has a higher boiling point than the chloroethane because of its higher atomic mass than the chloroethane.

Note:
- Don’t get confused in the alkanes and alkenes. Alkanes are the saturated compounds which consist of the -C-C single bonds in their compounds whereas the alkenes are the unsaturated compounds which consist of the -C=C double bond in their compounds.