Factors affecting equilibria - Effect of Concentration Change

Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?

\[\ce{PCl5 (g) ⇌ PCl3 (g) + Cl2 (g)}\]

The pH of neutral water at 25°C is 7.0. As the temperature increases, ionisation of water increases, however, the concentration of \[\ce{H+}\] ions and \[\ce{OH-}\] ions are equal. What will be the pH of pure water at 60°C?

Does the number of moles of reaction products increase, decrease or remain same when each of the following equilibria is subjected to a decrease in pressure by increasing the volume?

\[\ce{CaO (s) + CO2 (g) ⇌ CaCO3 (s)}\]

Which of the following statements is incorrect?

On the basis of Le Chatelier principle explain how temperature and pressure can be adjusted to increase the yield of ammonia in the following reaction.

\[\ce{N2 (g) + 3H2 (g) ⇌ 2NH3 (g) ∆H = - 92.38 kJ mol^{-1}}\]

What will be the effect of addition of argon to the above reaction mixture at constant volume?