To determine the direction in which the reaction shifts when [tex]\( SO_3 \)[/tex] is added to the solution, we need to consider Le Chatelier's Principle. According to Le Chatelier's Principle, when a system at equilibrium is disturbed by an external change, the system shifts in a direction that counteracts this disturbance to restore equilibrium.
Given the reaction:
[tex]\[
2 SO_2(g) + O_2(g) \rightleftharpoons 2 SO_3(g) + 198 \, \text{kJ}
\][/tex]
Here, [tex]\( SO_3 \)[/tex] is a product of the reaction. When additional [tex]\( SO_3 \)[/tex] is introduced into the system, the concentration of [tex]\( SO_3 \)[/tex] increases, disturbing the equilibrium.
Le Chatelier's Principle suggests that the system will attempt to reduce the disturbance (increased [tex]\( SO_3 \)[/tex]) by consuming the excess product. To achieve this, the reaction will shift towards the reactants.
Thus, the reaction will shift to the left, converting some of the [tex]\( SO_3 \)[/tex] back into [tex]\( SO_2 \)[/tex] and [tex]\( O_2 \)[/tex], in an effort to restore equilibrium.
Therefore, the correct answer is:
C. The reaction shifts left or to reactants.
