A chemical reaction has a ΔH of −150 kJ mol⁻¹ and the activation energy for its reverse reaction is 350 kJ mol⁻¹ - VCE - SSCE Chemistry - Question 8 - 2007 - Paper 1

To find the activation energy ( E_a) of the forward reaction, we can use the relationship between the activation energies of the forward and reverse reactions as well as the enthalpy change ( ΔH). This relationship is given by the equation: $E_{a, ext{forward}} = E_{a, ext{reverse}} + riangle H$

Given that:

ΔH = −150 kJ mol⁻¹ (for the forward reaction)

E_{a, ext{reverse}} = 350 kJ mol⁻¹

Substituting these values into the equation:

$E_{a, ext{forward}} = 350 ext{ kJ mol}^{-1} + (-150 ext{ kJ mol}^{-1})$ $E_{a, ext{forward}} = 350 - 150$ $E_{a, ext{forward}} = 200 ext{ kJ mol}^{-1}$

Thus, the activation energy of the forward reaction is +200 kJ mol⁻¹, which corresponds to option B.