At $473 \ K$,the equilibrium constant $K_{c}$ for the decomposition of phosphorus pentachloride is $8.3 \times 10^{-3}$. If the decomposition is depicted as:
$PCl_{5(g)} \longleftrightarrow PCl_{3(g)} + Cl_{2(g)} \quad \Delta_{r}H^{\circ} = 124.0 \ kJ \ mol^{-1}$
$(a)$ Write an expression for $K_{c}$ for the reaction.
$(b)$ What is the value of $K_{c}$ for the reverse reaction at the same temperature?
$(c)$ What would be the effect on $K_{c}$ if:
$(i)$ more $PCl_{5}$ is added?
$(ii)$ pressure is increased?
$(iii)$ the temperature is increased?

When $2 \ L$ of $CO_2$ is heated with graphite,the volume of gases collected is $3 \ L$. Calculate the number of moles of $CO$ produced at $STP$.

The reaction $2H_2S_{(g)} \rightleftharpoons 2H_{2_{(g)}} + S_{2_{(g)}}$ is in equilibrium. If $0.5 \ mol$ of $H_2S$,$0.10 \ mol$ of $H_2$,and $0.4 \ mol$ of $S_2$ are taken in a $1 \ L$ vessel,the value of the equilibrium constant $(K)$ is .... $mol \ L^{-1}$.

Which of the following statements regarding a chemical equilibrium is wrong?

Equilibrium constants for the following reactions are given (pressure in $atm$) for the reactions at $0\,^{\circ}C$. Select the option mentioning the correct order of True $(T)$ or False $(F)$ statements:
$(A) \ A \cdot 6H_2O_{(s)} \rightleftharpoons A \cdot 2H_2O_{(s)} + 4H_2O_{(g)}; \ K_P = 1.6 \times 10^{-11}$
$(B) \ B \cdot 12H_2O_{(s)} \rightleftharpoons B \cdot 7H_2O_{(s)} + 5H_2O_{(g)}; \ K_P = 2.43 \times 10^{-13}$
$(C) \ C \cdot 10H_2O_{(s)} \rightleftharpoons C_{(s)} + 10H_2O_{(g)}; \ K_P = 10^{-30}$
Aqueous tension of $H_2O$ at $0\,^{\circ}C$ is given as $0.76 \ torr$.
$(I)$ The most effective drying agent will be $C_{(s)}$ out of $C_{(s)}$,$B \cdot 7H_2O_{(s)}$,and $A \cdot 2H_2O_{(s)}$.
$(II)$ At $0\,^{\circ}C$,$A \cdot 6H_2O_{(s)}$ and $B \cdot 12H_2O_{(s)}$ will be efflorescent.
$(III)$ If $R.H.$ is less than $100\%$ in a chamber at $0\,^{\circ}C$,then none of the substances can act as deliquescent.

Which of the following is correct for the equilibrium shown below?
$2CH_3COOH \rightleftharpoons (CH_3COOH)_2$
(Equilibrium constants for the reaction in water and benzene are $K_{Water}$ and $K_{Benzene}$ respectively.)