In the reaction, represented by, 2SO₂ + O₂ ⇋ 2SO₃; ΔH = -42 kcal; the forward reaction will be favoured by

Le Chatelier's principle says that for an exothermic reaction decrease in temperature favours the forward reaction and for a reaction if $$\Delta n < 0$$   the increase in pressure favours the forward reaction and for a reaction if $$\Delta n > 0$$   the increase in pressure favours the backward reaction. Since the given reaction is having $$\Delta n < 0$$   increase in pressure favours the forward reaction.