If at 298 K the bond energies of C - H, C - C, C = C and H - H bonds are respectively 414, 347, 615 and 435 kJ/mol, the value of enthalpy change for the reaction
H₂C = CH₂(g) + H₂(g) $$\to$$ H₃C - CH₃(g) at 298 K will be :

The solubility in water of a sparingly soluble salt AB₂ is 1.0 $$\times$$ 10^-5 mol L^-1. Its solubility product number will be :

Consider the reaction equilibrium
2 SO₂ (g) + O₂ (g) $$\leftrightharpoons$$ 2 SO₃ (g); $$\Delta H^o$$ = -198 kJ
One the basis of Le Chatelier's principle, the condition favourable for the forward reaction is :

For the reaction equilibrium
N₂O₄ (g) $$\leftrightharpoons$$ 2NO₂ (g)
the concentrations of N₂O₄ and NO₂ at equilibrium are 4.8 $$\times$$ 10^-2 and 1.2 $$\times$$ 10^-2 mol L^-1 respectively. The value of K_c for the reaction is