Question

Increase of pressure always increases?
A.Always increases the boiling point of liquid.
B.Always decreases the melting point of solid.
C.Decreases the melting points of solid showing compression on fusion.
D.Increases the melting point of solid showing expansion on fusion

Answer 1

Hint: To solve this question, we have to remind ourselves with the ideal gas law \[PV = nRT\] , all the behaviour of gases is explained using this formula only. So when we increase the temperature of the gas, its pressure should also increase.

Complete answer: Pressure can be defined as the force exerted by the particles per unit of the area of the container.
Boiling point is the temperature of the liquid at which it starts to convert in a gaseous phase. Once this temperature is attained, liquid starts evaporating and the temperature remains constant till all the molecules of the liquid changes to the gaseous phase. Boiling temperature is the temperature at which the liquid and the gaseous phase is in equilibrium.
Liquids boil when their vapour pressure is equal to the pressure exerted on the liquid by the surrounding particles. So as the pressure keeps on increasing, accordingly its temperature also increases.
So from above basic knowledge, we can say this question has multiple correct answers.
So, the option: A. Always increases the boiling point of liquid.
C.Decreases the melting points of solid showing compression on fusion.
D.Increases the melting point of solid showing expansion on fusion
And hence options A,C and D are correct answers.

Note:
Melting point of the substance is the temperature at which it starts changing from the liquid to the solid phase. At melting temperature, the liquid and the solid remain in the equilibrium state. Also keep in mind that temperature is directly proportional to the pressure of the gas. With the increase in pressure of the gas, its temperature also increases.