Equilibrium Constant and Catalysts

Equilibrium constant (Kc) is a measure of the position of a reversible reaction at equilibrium. It is defined as the ratio of the concentrations of products to reactants, each raised to their stoichiometric coefficients. Kc is a characteristic of a given reaction at a particular temperature and pressure.

Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process. They work by lowering the activation energy required for the reaction to occur. Catalysts do not affect the equilibrium position of a reaction.

Effect of Catalysts on Equilibrium Constant

When a catalyst is added to a reversible reaction in equilibrium state, the equilibrium constant (Kc) does not change. This is because catalysts increase the rates of both the forward and reverse reactions equally. The net effect is that the reaction reaches equilibrium faster, but the position of equilibrium remains the same.

For example, consider the reversible reaction:

A + B ⇌ C + D

If a catalyst is added to this reaction, it increases the rates of both the forward and reverse reactions:

A + B ⇌ C + D

Catalyst

A + B ⇌ C + D

The net effect is that the reaction reaches equilibrium faster, but the position of equilibrium remains the same. The equilibrium constant (Kc) remains unchanged.

Conclusion

In conclusion, the addition of a catalyst to a reversible reaction at equilibrium does not affect the position of equilibrium. The equilibrium constant (Kc) remains the same. Catalysts increase the rates of both the forward and reverse reactions equally, resulting in a faster attainment of equilibrium.

Catalyst does not alter the Position of Equilibrium but it helps to attain equilibrium position quickly therefore equilibrium constant value doesn't change as the position of equilibrium remains same.