Step 1: Understanding the Concept:
Le Chatelier’s Principle dictates how an equilibrium system responds to external changes in temperature, pressure, or the addition of a catalyst to minimize that change.
Step 2: Key Formula or Approach:
Assess the effect of Temperature (based on $\Delta H$) and Pressure (based on $\Delta n_g$) on the equilibrium position. A catalyst affects the rate of approaching equilibrium, not the final equilibrium amount.
Step 3: Detailed Explanation:
1. Temperature Effect: The reaction is specified as exothermic ($\Delta H = -q$ kJ). According to Le Chatelier’s Principle, increasing the temperature shifts an exothermic equilibrium backward (to the reactants side), while decreasing it shifts it forward (to the products side). Thus, temperature significantly affects the amount of $A_{3}B$ formed.
2. Pressure Effect: On the reactant side, there are $4$ moles of gas ($3+1$). On the product side, there is $1$ mole of gas. An increase in pressure will shift the equilibrium toward the side with fewer moles of gas to reduce pressure. A decrease shifts it toward more moles. Thus, pressure affects the yield of $A_3B$.
3. Catalyst Effect: A catalyst lowers the activation energy for both forward and reverse reactions equally. It only speeds up the time taken to reach equilibrium but does {not} alter the final equilibrium concentration or amounts.
Step 4: Final Answer:
Both temperature and pressure affect the equilibrium concentration of the product.