Question

Assertion: On heating a solid, its particles start vibrating vigorously.

Reason: At the melting point, the particles of the solid acquire sufficient kinetic energy to overcome the strong forces of attraction between them and move away from their positions, thus, the solid changes into a liquid.

Mark the correct choice:

• A. Both A and R are correct and R is the correct explanation of A.
• B. Both A and R are correct and R is not the correct explanation of A.
• C. A is correct but R is incorrect.
• D. A is incorrect but R is correct.
• E. Both A and R are incorrect.

Answer 1

The correct option is A

Both A and R are correct and R is the correct explanation of A.

The explanation for the Assertion statement:

By increasing temperature, solids particles gain energy and vibrate vigorously. This allows the particle to move faster and intermolecular forces also increased.

The explanation for the Reason statement:

• The melting point is defined as the point at which materials change from a solid to a liquid
• Solid particles are tightly packed
• When we heat a solid, its particles gain energy and vibrate vigorously
• Due to heating, the temperature increases, and when the temperature reaches the melting point
• The forces of attraction between the molecules are overcome and this enables the particles to move around faster
• The intermolecular space increases and the solid ice changes into liquid

Hence, the correct option is A.