Answer
The number of $H_2$ and $I_2$ molecules would decrease more quickly than in the original series, and the number of $HI$ molecules would increase faster.
The number of $H_2$, $I_2$ and $HI$ would also start to be constant faster.
Work Step by Step
Using a catalyst would increase the rate of the chemical reaction, but it does not change anything else.
Thus, the process of reaching equilibrium would occur in less steps, making the change of reactants and products faster.
