CAIE A-Level Chemistry AS 7 Equilibria Questions

When a sample of ammonium chloride is warmed it decomposes into ammonia and hydrogen chloride gas.

When the mixture of hot ammonia and hydrogen chloride gases hit a cold surface, a white solid of ammonium chloride reforms.

Which statements are correct?
1 Reaction 1 is in dynamic equilibrium.
2 Reaction 1 is reversible.
3 Reaction 1 is an endothermic reaction.

Graphs can be drawn to show the percentage of ammonia at equilibrium when nitrogen and hydrogen are mixed at different temperatures and pressures.

Which diagram correctly represents these two graphs?

Diethylzinc, $\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{Zn}$, is added to NaOH(aq). Two reactions occur.

reaction $1 \quad\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{Zn}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{ZnO}+2 \mathrm{C}_{2} \mathrm{H}_{6}$

reaction $2 \quad \mathrm{H}_{2} \mathrm{O}+\mathrm{ZnO}+2 \mathrm{OH}^{-} \rightarrow \mathrm{Zn}(\mathrm{OH})_{4}{ }^{2-}$

In these reactions, which compounds act as Brønsted-Lowry acids?

The units of $K_{\mathrm{c}}$ for an equilibrium reaction are $\mathrm{mol}^{-1} \mathrm{dm}^{3}$.
What could be the equation for the equilibrium?

1$\mathrm{~A}(\mathrm{aq})+\mathrm{B}(\mathrm{aq}) \rightleftharpoons \mathrm{C}(\mathrm{s})+\mathrm{D}(\mathrm{aq})$
2 $\mathrm{P}(\mathrm{aq})+\mathrm{Q}(\mathrm{aq}) \rightleftharpoons \mathrm{R}(\mathrm{aq})$
3 $\mathrm{~W}(\mathrm{aq})+2 \mathrm{X}(\mathrm{aq}) \rightleftharpoons \mathrm{Y}(\mathrm{aq})+\mathrm{Z}(\mathrm{aq})$