Chemical Equilibrium Part 2

$\mathrm{CO}(g)+3\mathrm{H}_2(g)\rightleftharpoons \mathrm{CH}_4(g)+\mathrm{H}_2\mathrm{O}(g)$$\Delta n_g=(1+1)-(1+3)=-2$Since $\Delta n_g<0$, increasing pressure at constant temperature shifts the equilibrium in the forward direction, so (B) is correct.Increasing pressure by compression decreases the volume, so the concentrations of the gaseous reactants and products increase; hence (A) is correct.The equilibrium constant $K$ depends only on temperature.At constant temperature, $K$ remains unchanged, so (C) is incorrect.(D) is incorrect because the concentrations of reactants and products do not remain the same even though $K$ remains unchanged.Therefore, the correct combination is (A) and (B) only.