Question

Arrange the bromine-containing compounds CaBr2, Br2, NBr3, CBr4 in order of increasing predicted boiling point.

Answer 1

Explanation:

In an ionic compound, there will be strong force of attraction between the combining atoms due to the opposite charges present on them.

For example, $CaBr_{2}$ is an ionic compound where calcium has a +2 charge and each bromine atom has a -1 charge.

Therefore, in order to break the bond we need to provide more heat. Hence, boiling point of calcium bromide will be the highest.

$NBr_{3}$ is a covalent compound and as nitrogen is more electronegative in nature and also has a lone pair of electron hence, there will be a net dipole moment.

$CBr_{4}$ is also a covalent compound. And, as bromine is more electronegative than carbon atom so, dipole moment is in the outwards direction. Hence, in $CBr_{4}$ there will be zero dipole moment.

Therefore, its boiling is less than the boiling point of $NBr_{3}$.

$Br_{2}$ is a covalent compound and there will be no dipole moment.

Thus, we can conclude that given bromine-containing compounds are placed in their increasing boiling point order as follows.

    $Br_{2}$ < $CBr_{4}$ < $NBr_{3}$ < $CaBr_{2}$