Question

The amount of heat energy needed to change state from solid to liquid or from liquid to gas depends on the strength of

• A. Inter-molecular force
• B. Inter-molecular spaces
• C. Inter-molecular movement
• D. Internal energy

Answer 1

The correct option is A

Inter-molecular force

The explanation for the correct option :

(a) Inter-molecular force:

• The process in which solid changes into liquid is called melting or fusion.
• The temperature at which a solid changes into liquid at atmospheric pressure is called its melting point.
• Higher the melting point higher the force of attraction between its particles

The explanation for the incorrect option :

(b)Inter-molecular spaces:

• The inter-molecular space is high in between the particles of gas.
• The order of inter-molecular spaces are$\mathrm{Gas}>\mathrm{Lliquid}>\mathrm{Solid}$.

(c) Inter-molecular movement:

• Inter molecular moments are more in the case of gas, because of the weak inter-molecular force of attraction.
• The order of inter-molecular movement$\mathrm{Gas}>\mathrm{Liquid}>\mathrm{Solid}$.

(d) Internal energy:

• Internal energy is more in the case of solid because of the strong intermolecular force of attraction.
• The order of internal energy $\mathrm{Solid}>\mathrm{Liquid}>\mathrm{Gas}$

Thus, Option (A) is the correct i.e Inter-molecular force.