Question

For the reaction $H_2$ (g) + $I_2$ (g) $\leftrightharpoons$ 2HI(g)the equilibrium constant $K_p$ changes with

• A. Total pressure
• B. catalyst
• C. the amounts of $H_2$ and $I_2$ present
• D. temperature

Answer 1

The correct option is D

temperature

Always remember: When we talk about a "particular” equilibrium, we uniquely identify it by a temperature. Unless otherwise specified, the temperature does not change.
Characteristics of equilibrium constant ($K_p$)
1.For a given reaction, the value of the equilibrium constant depends only on the temperature.
2.It is independent of the direction from which the equilibrium is attained or the initial concentrations of the reacting species
3.It is independent of Volume or the presence of catalysts
4.$K_p$ does not change due to the presence of inert gases
All these shall be applicable for the other equilibrium constant K_c as well. The difference between the two is the way in which the "active mass” is expressed. If we use molar concentrations then we are utilizing $K_c$. On the other hand, if we use partial pressures, then $K_p$ is implied. Other active masses like mole fractions might also be used to derive a new form of equilibrium constant.