Question

What is Henry law and colligative properties?

Answer 1

Henry's law is a gas law that states that the amount of dissolved gas is proportional to its partial pressure in the gas phase. 
colligative properties are properties which depends upon the no. of particles of solute present on the surface

Answer 2

Hey !!

It states that at a constant temperature, the solubility of a gas in a liquid is directly proportional to the pressure of the Gas.

→ The most commonly used form of Henry's Law states that the partial pressure of a gas in vapour phase is proportional to the mole fraction of the gas (x) in the solution and is expressed as     

                     P = Kh x                      

Here Kh is the Henry's constant and x is the mole fraction of the gas.

COLLIGATIVE PROPERTIES

Those properties which depend on the number of solute particles (molecules , atoms or ion ) but not upon their nature are called colligative properties.

Hope it helps you !