Which information can be obtained from Le Chatelier’s principle?

Shift in equilibrium position on changing P, T and concentration

The correct answer is option 1. Shift in equilibrium position on changing P, T and concentration.

Le Chatelier’s principle primarily helps in understanding how chemical equilibria respond to changes in conditions such as pressure, temperature, and concentration. Let's analyze each option to determine which one aligns with the principles derived from Le Chatelier's principle:

1. Shift in equilibrium position on changing P, T, and concentration:

The option is correct. Le Chatelier's principle predicts how equilibrium will shift in response to changes in pressure (P), temperature (T), and concentration. It explains whether the equilibrium will shift towards the reactants or products to counteract changes in these factors.

2. Dissociation constant of weak acid:

The option is incorrect. The dissociation constant of a weak acid (or base) is determined by the equilibrium concentrations of the acid, its conjugate base, and the hydrogen ion concentration in solution, not by Le Chatelier's principle.

3. Energy change in reaction:

The option is incorrect. Le Chatelier's principle does not directly provide information about the energy change (enthalpy change, ΔH) in a reaction. It focuses on the direction of equilibrium shift in response to changes in conditions rather than on the quantitative energy changes

4. Equilibrium constant of a chemical reaction:

The option is incorrect. While Le Chatelier's principle describes how equilibrium responds to changes, it does not directly determine the numerical value of the equilibrium constant (\(K\)) for a reaction. The equilibrium constant is a thermodynamic quantity that depends on the concentrations (or pressures) of reactants and products at equilibrium.

Conclusion: From the options provided, the information that can be obtained directly from Le Chatelier's principle is: (1) Shift in equilibrium position on changing P, T, and concentration.

This statement aligns with the fundamental principle of Le Chatelier, which predicts the direction of equilibrium shift in response to changes in pressure, temperature, and concentration of reactants and products.