A reaction occurs spontaneously if

Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction ?

The work done during the expansion of a gas from a volume of 4 dm³ to 6 dm³ against a constant external pressure of 3 atm is (1 L atm = 101.32 J)

If the bond energies of H $$-$$ H, Br $$-$$ Br, and H $$-$$ Br are 433, 192 and 364 kJ mol^$$-$$1 respectively, the $$\Delta $$H^o for the reaction

H_2(g) + Br_2(g) $$ \to $$ 2HBr_(g) is