Question

For the reaction, A ⇌ B, E_a = 50 kJ mol⁻¹ and ΔH = −20 kJ mol⁻¹. When a catalyst is added, E_a decreases by 10 kJ mol⁻¹. What is the E_a for the backward reaction in the presence of catalyst?

• A. 60 kJ mol⁻¹
• B. 40 kJ mol⁻¹
• C. 70 kJ mol⁻¹
• D. 20 kJ mol⁻¹

Hint:

The backward activation energy is calculated using E a,b=Ea,f−ΔH.

Answer 1

The Correct Option is A

The backward activation energy is calculated as Ea,b​=Ea,f​−ΔH, giving Ea,b​=40−(−20)=60kJ/mol when the catalyst reduces the forward activation energy to 40 kJ/mol.