When a solute is added to a solution the boiling point becomes higher because the solutes and solvents are attracted to each other making it difficult for them to escape into a gas. This means that more energy is needed to reach the boiling point.
To understand osmotic pressure, it is helpful to know the basics of osmosis. Osmosis is when molecules of a solvent pass through a semipermeable membrane to the more concentrated side of a u-tube. A semipermeable membrane is a membrane that will allow certain molecules to pass through it, in the example of osmosis it allows the solvent to pass through to lower its energy. This is connected to osmotic pressure because that is the pressure used to stop the molecules from passing through the semi-permeable membrane.
Some solutes have different effects on the solutions. For example, ionic solutes dissolve and split when placed in a solution. The ions split into positives and negatives and produce multiple ion particles. This makes them affect colligative properties more than molecular