To address the question of which direction the reaction will shift when more HI is added, let's analyze the scenario using Le Chatelier's Principle, which helps predict the effect of a change in conditions on a chemical equilibrium.
Given the reaction:
[tex]\[
51.8 \text{ kJ} + H_2(g) + I_2(g) \rightleftharpoons 2 \text{HI}(g)
\][/tex]
Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.
### Step-by-Step Analysis:
1. Identify the Condition Change:
In this case, the change is the addition of more HI, a product of the reaction.
2. Determine the Effect of the Change:
According to Le Chatelier's Principle, adding more of a product will cause the equilibrium to shift in the direction that consumes the added product. This means the system will shift toward the reactants to counteract the increase in HI concentration.
3. Conclusion:
To re-establish equilibrium, the reaction will shift to the left, towards the reactants. This shift means that more H2 and I2 will be produced while some of the added HI will be consumed.
### Final Answer:
A. The reaction shifts left or to reactants.
This is the correct choice since adding more HI causes the equilibrium to shift toward the side that produces reactants, thereby decreasing the concentration of excess HI.
