Answer:
B. X and Y only
Explanation:
Hello,
In this case, by considering the Le Chatelier's principle, if we desire an increase in the hydrogen iodide amount, based on the given reaction, two procedures are needed:
- Add HCl(g) to the reaction vessel: because the addition of a reagent shifts the reaction rightwards.
- Add I2(s) to the reaction vessel: by cause of the same aforesaid reason.
Therefore, the answer is: B. X and Y only.
Z statement is not true since the change in the mole number for the reaction is zero (2+1-2-1=0) considering each species' stoichiometric coefficients.
Best regards.