A catalyst has no effect on ?

Hint :A catalyst has no effect on the position of equilibrium of the reaction. Catalyst increases the rate of a reaction by lowering the activation energy so that more reactant molecules collide with enough energy to surmount the smaller energy barrier.

Complete Step By Step Answer:
$ - $Equilibrium constants are not changed if you add a catalyst. The only thing that changes an equilibrium constant is a change of temperature.
$ - $This is because a catalyst speeds up the forward and back reaction to the same extent and adding a catalyst does not affect the relative rates of the two reactions, it cannot affect the position of equilibrium. A catalyst speeds up the rate at which a reaction reaches dynamic equilibrium
$ - $According to Le Chatelier's principle how an equilibrium shifts when the conditions of an equilibrium are changed. The direction of shift can be predicted for changes in concentrations, temperature, or pressure. Catalysts do not affect the position of an equilibrium; they help reactions achieve equilibrium faster.
$ - $By lowering the energy of the transition state, catalysts reduce the required energy of activation to allow a reaction to proceed and, in the case of a reversible reaction, reach equilibrium more rapidly.

Note :
A good catalyst needs to adsorb the reactant molecules strongly enough for them to react, but not so strongly that the product molecules stick more or less permanently to the surface. Silver, for example, isn't a good catalyst because it doesn't form strong enough attachments with reactant molecules.