Answer: when product D is removed from the reaction, we should expect a shift of the reaction towards the product's side (shift to the right)
Step-by-step explanation:
The question requires us to predict the change in the following reaction when the product D is removed:
1A(s) + 2B(l) + heat ↔ 3C (g) + 4D (s)
To solve this problem, we can apply Le Chatelier's principle, which states that changes in temperature, pressure, volume or concentration of reactants/products in a system will result in predictable changes in the system in order to achieve a new state of equilibrium.
According to the Le Chatelier's principle, if we increase the concentration of any reactant in the system, the equilibrium will shift towards the product's side (right shift) in order to consume the "excess" reactant added. In a similar way, if we decrease the concentration of a reactant in the system, the system tends to shift towards the reactant's side (left shift) in order to restabilish the equilibrium.
When we consider the changes in concentration of products we can say that adding more of a product in the system will shift the equilibrium to the reactant's side, while decreasing the concentration of a product will shift the equilibrium to the product's side.
Therefore, when product D is removed from the reaction, we should expect a shift of the reaction towards the product's side (shift to the right).