Q.(a) Using Le-Chatelier's principle explain the effect of the following factors on equilibrium.

By Le Chatelier's principle, an equilibrium always shifts in the direction that opposes/counteracts an imposed change; applying this to concentration, pressure, temperature, catalyst, and inert gas gives five distinct, predictable effects.

Le Chatelier's principle states: "If a system at equilibrium is subjected to a change in concentration, pressure, or temperature, the equilibrium shifts in the direction that tends to counteract the effect of the change."

1. Effect of Concentration: Increasing the concentration of a reactant shifts the equilibrium in the forward direction (towards products), to consume some of the added reactant and partially offset the increase. Conversely, increasing the concentration of a product shifts the equilibrium backward (towards reactants). Removing a substance has the opposite effect, shifting equilibrium to replace what was removed.
2. Effect of Pressure: Increasing the total pressure (by decreasing volume) shifts the equilibrium towards the side with the SMALLER number of moles of gas, since that side occupies less volume and partially relieves the increased pressure. If both sides have equal moles of gas, pressure has no effect on the equilibrium position.
3. Effect of Temperature: Increasing temperature shifts the equilibrium in the ENDOTHERMIC direction (the direction that absorbs heat), since this partially counteracts the added heat. So for an exothermic forward reaction, increasing temperature shifts equilibrium backward (favours reactants); decreasing temperature favours the exothermic (forward) direction.
4. Effect of Catalyst: A catalyst lowers the activation energy for both the forward and the reverse reactions EQUALLY, so it speeds up the attainment of equilibrium but does NOT change the position of equilibrium or the value of the equilibrium constant — no shift occurs. …