Consider the following modifications to a sealed vessel containing a gaseous reaction mixture at equilibrium temperature T. The reaction is known *not* to be photochemical.
Modification I: The total pressure is increased by decreasing the volume of the container.
Modification II: Argon gas is injected at constant volume.
Modification III: A bright ultraviolet lamp is turned on, illuminating the vessel.
Modification IV: A small amount of a finely divided solid catalyst specific to the reaction is added.
(a) For each modification, indicate whether the *rate of the forward reaction* will increase, decrease, or remain essentially unchanged immediately after the modification is made.
(b) Choose *one* modification that you predicted would change the rate. Provide a detailed justification that refers explicitly to collision frequency or activation energy, as appropriate for that modification.
(c) For any modification you predicted would have negligible effect on rate, explain why the key factor that governs reaction rate is not significantly altered.