Niels Bohr postulated that electrons orbit the nucleus in orbits at discrete, set distances from the nucleus. What observation did he use to support thispostulate?

The temperature of the solute/solvent without any external effect would decrease.

Explanation:

As the bonding between the solute particles is really strong, therefore a large amount of energy is required to overcome these forces. So that the new bonding between the solute and solvent is created.

In order to achieve this, there will be a lot of energy required and that is through the heating process. So the solution will require energy so the solute will dissolve fully either by provision of external force i.e stirring or by heating.