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, 
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.
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.
is also a covalent compound. And, as bromine is more electronegative than carbon atom so, dipole moment is in the outwards direction. Hence, in there will be zero dipole moment.
Therefore, its boiling is less than the boiling point of .
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.
< < <
Answer:
A or D because the chemical reaction is long
The more solid a substance is, the less kinetic energy there is. This is because there is not a lot of space for the atoms in the solid state to move. However, in the gaseous state, the atoms are far apart with plenty of space, this lets them create a lot more kinetic energy. Solids have a lot more intermolecular forces because the atoms are together. The IMF (intermolecular force) is what lets the atoms/molecules stick together. In the solid state, all the atoms are stuck together with little to no room in between. In the liquid state, it has a lot of IMF but is weaker then the IMF in the solid state. This is why you have so much resistance when you try to move through water. In the gaseous state, there is little to no IMF because the atoms are all so far apart. This makes it easier for everyone to move around.
To answer your question more directly: As the substance is heated to its melting point, there is an increase in kinetic energy, but decrease in intermolecular forces.
