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

When rain is accompanied by a thunderstorm, the collected rain water will have a pH value :

In curing cement plasters water is sprinkled from time to time. This helps in :