Under which conditions of temperature and pressure is the dissociation of molecular hydrogen into atomic hydrogen favored?

In the reaction: $H_2S \rightleftharpoons 2H^{+} + S^{2-}$,when $NH_4OH$ is added,then

When $I_2$ dissociates to its atomic form the following reaction occurs:
$I_{2(g)} \rightleftharpoons 2I_{(g)} ; \Delta_r H^o = +150 \ kJ \ mol^{-1}$
The forward reaction is favoured at:

Consider the following reactions. In which cases is product formation favoured by decreased temperature?
$(a) \ N_{2(g)} + O_{2(g)} \rightleftharpoons 2NO_{(g)}; \ \Delta H^o = 181 \ kJ$
$(b) \ 2CO_{2(g)} \rightleftharpoons 2CO_{(g)} + O_{2(g)}; \ \Delta H^o = 566 \ kJ$
$(c) \ H_{2(g)} + I_{2(g)} \rightleftharpoons 2HI_{(g)}; \ \Delta H^o = -9.4 \ kJ$
$(d) \ H_{2(g)} + F_{2(g)} \rightleftharpoons 2HF_{(g)}; \ \Delta H^o = -541 \ kJ$

For the reaction $CO_{(g)} + H_2O_{(g)} \rightleftharpoons CO_{2(g)} + H_{2(g)}$,the equilibrium amount of $CO_{2(g)}$ increases by:

$A$ catalyst can affect a reversible reaction by