When a catalyst is added to a system,the:

Explain the effect of a catalyst on chemical equilibrium with examples.

Higher yield of $NO$ in $N_{2(g)} + O_{2(g)} \rightleftharpoons 2 NO_{(g)}$ can be obtained at [ $\Delta H$ of the reaction $= +180.7 \ kJ \ mol^{-1}$ ]
$A.$ Higher temperature
$B.$ Lower temperature
$C.$ Higher concentration of $N_2$
$D.$ Higher concentration of $O_2$
Choose the correct answer from the options given below:

The reaction $SO_2 + Cl_2 \rightleftharpoons SO_2Cl_2$ is exothermic. If some $SO_2$ is added to the equilibrium mixture at constant volume,then ...........

$(a)$ What is required in chemical synthesis? What will be done for that?
$(b)$ Write Le Chatelier's principle.

The yield of product in the reaction $A_{2(g)} + 2B_{(g)} \rightleftharpoons C_{(g)} + Q \ kJ$ would be high at