Equilibrium Tes...

The reaction, $$C_2H_6(g)\rightleftharpoons C_2H_4(g)+H_2(g)$$ is at equilibrium in a closed vessel at $$1000\ K$$. The enthalpy change $$(\Delta H)$$ for the reaction is $$137.0$$ $$kJ.mol^{-1}$$. Which one of the following actions would shift the equilibrium to the right?

Consider the reaction:
$${Cl}_{2}(aq)+{H}_{2}S(aq)\rightarrow S(s)+2{H}^{+}(aq)+2{Cl}^{-}(aq)$$

An excess of $$Ag_2CrO_4(s)$$ is added to a $$5\times 10^{-3}M$$ $$K_2CrO_4$$ solution. The concentration of $$Ag^+$$ in the solution is closest to.[Solubility product for $$Ag_2CrO_4=1.1\times 10^{-12}$$]

$$Au(s)\rightleftharpoons Au(l)$$

A gas $$X$$ when dissolved in water heat is evolved. Then solubility of $$X$$ will increase:

The solubility product constant $$Ksp$$ of $$Mg(OH)_{2}$$ is $$9.0\times 10^{-12}$$. If a solution is $$0.010\ M$$ with respect to $$Mg^{2+}$$ ion. What is the maximum hydroxide ion concentration which could be present without causing the precipitation of $$Mg(OH)_{2}$$?

$$1$$ litre buffer solution $$\left( HA+NaA \right) pH=4$$ , is mixed with  $$2$$ litre buffer solution $$\left( HA+NaA \right) pH=4.3$$. $$pH$$ of resulting solution if both solutions are initially $$0.1M$$ $$MA$$.
[Given $${ \left( { K }_{ a } \right)  }_{ HA }={ 10 }^{ -4 };\log { 2 } =0.3;\log { 3 } =0.48;\log { 5 } =0.7\quad $$]

Ammonia gas at $$15$$ atm is introduced in a rigid vessel at $$300$$K. At equilibrium, the total pressure of the vessel is found to be $$40.11$$ atm at $$300^0$$C. The degree of dissociation of $$NH_3$$ will be :

Solid $$Ba{({NO}_{3})}_{2}$$ is gradually dissoved in a $$1\times {10}^{-4}M$$ $${Na}_{2}{CO}_{3}$$ solution. At what minimum conc. of $${Ba}^{-2}$$ will a precipitate of $$Ba{CO}_{3}$$ begin to form? ($${K}_{sp}$$ for $$Ba{CO}_{3}=5.1\times {10}^{-9}$$)

Consider the following equilibrium system; $$2SO_{2(g)} + O_{2(g)} \rightleftharpoons 2SO_{3(g)}$$; some inert gas is added to the system at constant volume. Predict which of the following is true?