Final answer:
When the reaction 2 HI(g) ⇌ H2(g) + I2(g) is multiplied by three, the new equilibrium constant becomes the original constant raised to the third power.
Step-by-step explanation:
The magnitude of equilibrium constants (Kp) for the reaction involving hydrogen iodide (HI) depends on how the reaction is written. In the case of the reaction 2 HI(g) ⇌ H2(g) + I2(g), if we multiply the entire reaction by three, which gives us 6 HI(g) ⇌ 3 H2(g) + 3 I2(g), the new equilibrium constant will be the original constant raised to the power of three. This is because the equilibrium expression of a reaction is dependent on the stoichiometry of the balanced chemical equation. Therefore, if the original Kp is K, the new Kp for the multiplied reaction would be K3.