Question

Assertion (A): Rate constant increases with increase in temperature.
Reason (R): Increasing the temperature of the substance increases the fraction of molecules which collide with energies greater than activation energy.

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

Hint:

Temperature increases kinetic energy, so more molecules exceed activation energy → faster reactions.

Answer 1

The Correct Option is A

According to the Arrhenius equation: \[ k = A e^{-E_a/RT} \] where: - \( k \): rate constant - \( E_a \): activation energy - \( R \): gas constant - \( T \): temperature in Kelvin When temperature increases, \( e^{-E_a/RT} \) increases, hence \( k \) increases.
Also, more molecules have energy \(>E_a \), so the rate of reaction increases. \[ \boxed{\text{Both A and R are true and R explains A.}} \]