In the chemical reaction $A \rightleftharpoons B$,the system will be known to be in equilibrium when:

Addition of a catalyst in a system at equilibrium:

Among the following,the correct statement about the chemical equilibrium is

At what change in Gibbs free energy $(\Delta G)$ does a reaction reach equilibrium?

For the equilibrium, $H_{2}O_{(l)} \rightleftharpoons H_{2}O_{(g)},$ which of the following is correct?

Predict which of the following reactions will have an appreciable concentration of both reactants and products:
$(a)$ $Cl_{2(g)} \longleftrightarrow 2Cl_{(g)};$ $K_{c}=5 \times 10^{-39}$
$(b)$ $Cl_{2(g)}+2NO_{(g)} \longleftrightarrow 2NOCl_{(g)};$ $K_{c}=3.7 \times 10^{8}$
$(c)$ $Cl_{2(g)}+2NO_{2(g)} \longleftrightarrow 2NO_{2}Cl_{(g)};$ $K_{c}=1.8$