Statement (A): Addition of an inert gas at equilibrium at constant volume does not affect equilibrium. Statement (B): Addition of a catalyst does not affect the position of equilibrium. Choose the correct option.
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Catalyst changes rate, not equilibrium position; inert gas affects equilibrium only at constant pressure, not constant volume.
Step 1: Analyze Statement A (inert gas at constant volume).
When an inert gas is added at constant volume, total pressure increases but partial pressures of reacting gases remain unchanged. Since equilibrium depends on partial pressures (or concentrations), the equilibrium position does not shift. Therefore, Statement A is correct.
Step 2: Understand physical reasoning.
At constant volume, mole fraction and concentration of reactants remain unchanged. Since equilibrium constant depends only on temperature, no change occurs in equilibrium composition.
Step 3: Analyze Statement B (catalyst effect).
A catalyst only lowers activation energy and increases rate of both forward and reverse reactions equally. It does not change equilibrium constant or equilibrium position. Hence equilibrium remains unaffected.
Step 4: Thermodynamic interpretation.
Equilibrium position depends only on Gibbs free energy difference, not on reaction pathway. A catalyst does not change $\Delta G$, so equilibrium remains unchanged.
Step 5: Final evaluation.
Both statements correctly describe fundamental equilibrium properties.
Step 6: Final conclusion.
\[
\boxed{\text{Both statements are correct}}
\]
