NEET Chemistry: Le Chatelier’s principle Practice Questions

Correct answer: B — The right side (products)

According to Le Chatelier's principle, if the concentration of a reactant (A) is increased, the system attempts to counteract this change by consuming the added reactant. This causes the equilibrium to shift in the forward direction to consume A and form more products.

Correct answer: B — The right side (products).

If a product is removed, the system attempts to replace the removed product by shifting the equilibrium to the right, thus increasing the concentration of the remaining products to re-establish equilibrium.

Correct answer: D — Increasing the temperature.

For an endothermic reaction (where heat is a reactant), increasing the temperature shifts the equilibrium to the right (forward direction) to consume the added heat.

Correct answer: B — The side with higher concentration of products

Reducing the concentration of a product creates a stress. The system compensates by shifting the reaction in the forward direction (towards the products) to replenish the reduced reactant, thereby increasing the product concentration.

Correct answer: C — The equilibrium will shift to the left

According to Le Chatelier's principle, when a stress (like adding a substance) is applied to a system at equilibrium, the system shifts in a direction that counteracts that stress. Adding an excess of a product (B⁻) increases the concentration of products, causing the equilibrium to shift in the reverse direction (to the left) to consume the added solute.

Correct answer: B — Increasing the pressure

Decreasing the volume increases the pressure, which favors the side with fewer moles of gas to alleviate the increased pressure.

Correct answer: C — Absorbs heat (endothermic direction)

For an endothermic reaction (ΔH > 0), increasing the temperature shifts the equilibrium towards the forward reaction (product formation) to consume the added heat.

Correct answer: C — Le Chatelier's Principle

Le Chatelier's principle states that if a change of condition (like concentration, temperature, or pressure) is applied to a system in equilibrium, the system will shift in a direction that counteracts that change to establish a new equilibrium.

Correct answer: D — There is no change in the equilibrium concentration of NH₃

Adding an inert gas at constant volume changes the total pressure but does not change the partial pressures or the partial concentrations of the reacting gases. Therefore, the equilibrium position remains unchanged.

Correct answer: D — K_c increases

For an endothermic reaction, increasing the temperature shifts the equilibrium towards the products, increasing K_c. For an exothermic reaction, the reverse happens. In general, a change in temperature affects the equilibrium constant based on the sign of ΔH of the reaction.

Correct answer: C — To the left (reverse direction)

Decreasing the volume increases the pressure. According to Le Chatelier's principle, the system shifts to reduce the pressure by favoring the side with fewer moles of gas. In this case, the left side (N₂ + 3H₂) has 4 moles of gas, and the right side (NH₃) has 2 moles of gas. Therefore, the equilibrium shifts to the right (forward direction) to relieve the increased pressure.

Correct answer: B — Removing a reactant from the system

Removing a reactant from the system decreases its concentration. To counteract this and restore equilibrium, the system shifts in the direction that produces more of that removed reactant, which is the forward direction (towards reactants).

Correct answer: B — To the left (reactants)

When a product concentration is increased, the system shifts in the reverse direction (left) to consume the excess product and re-establish equilibrium.