What happens when an inert gas is added at constant pressure to a reversible decomposition reaction that is in equilibrium?

Which of the following conditions will favor the maximum yield of $SO_3$ according to Le Chatelier's principle for the reaction: $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$ $(\Delta H = -198.2 \, kJ/mol)$?

In which of the following reactions will the amount of products not increase upon increasing the pressure?

The yellow solution of $Na_2CrO_4$ changes to orange red on passing $CO_2$ gas due to the formation of:

The binding of oxygen by haemoglobin $(Hb)$ forming $(HbO_2)$ is partially regulated by the concentration of $H_3O^{+}$ and dissolved $CO_2$ in blood.
$HbO_2 + H_3O^{+} + CO_2 \rightleftharpoons (H^{+} - Hb - CO_2) + O_2 + H_2O$
Release of $O_2$ is favoured when there is:

For the chemical reaction: $BaO_{2(s)} \rightleftharpoons BaO_{(s)} + \frac{1}{2} O_{2(g)}$,$\Delta H = +ve$. At equilibrium,the pressure of $O_2$ depends upon: