Rate of reaction(2021 VCE)

1.An equilibrium mixture of four gases is represented by the following equation

The graph below shows the rate of the forward and reverse reactions versus time. A single change is made to the equilibrium mixture at time t1 and equilibrium is re-established at time t2 .

Which one of the following is consistent with the information given above?
A. Argon is added to the equilibrium mixture at time t1.
B. At time t1 reactants are removed from the equilibrium mixture.
C. The amount of products is higher at time t2 compared to just before time t1.
D. The change made at time t1 results in an increase in the equilibrium constant at time t2 .


2. Which one of the following statements describes the effect that adding a catalyst will have on the energy profile diagram for an exothermic reaction?
A. The energy of the products will remain the same.
B. The shape of the energy profile diagram will remain the same.
C. The peak of the energy profile will move to the left as the reaction rate increases.
D. The activation energy will be lowered by the same proportion in the forward and reverse reactions.