For the equilibrium reaction 2SO2g O2g 2SOgg AHxn198 kJmol

For the equilibrium reaction 2SO2(g) + O2(g) 2SOg(g). AH.xn--198 kJ/mol. Which one of these factors would cause the equilibrium constant to increase? A. Add SO2 gas B. Decrease the temparature C. Remove 02 gas D.Add a catalyst

Solution

Ans. For a reaction in equlibrium, the change in the amount of the reactants or the addition of catalyst do not have effect on the equilibrium constant. The equilibrium constant is dependant only on the temperature of the reaction and whether the reaction is exothermic or endothermic.

For the given reaction, H^o_rxn = -198 KJ/mol.

The negative value of change in enthalpy denotes that the reaction is an exothermic reaction.

For an exothermic reaction, decreasing the temperature increases the equilibrium constant. Whereas, increasing temperature would decrease the equilibrium constant.

It is the opposite for endothermic reactions.

Since the reaction given is an exothermic reaction, decreasing the temperature will increase the equilibrium constant.

Therefore, second option is correct. That is, decrease the temperature.