The addition of a catalyst during a chemical reaction alters which of the following quantities?

For a first-order reaction,if the rate constant is $k_1$ at temperature $T_1$ and $k_2$ at temperature $T_2$,which of the following relations is correct? ($E_a$ = activation energy)

When a biochemical reaction is carried out in a laboratory without the presence of enzymes,the rate of reaction is $10^{-6}$ times slower. What will be the activation energy $(E_a)$ in the presence of enzymes?

Which of the following statements is not true according to the collision theory of reaction rates?

What is the slope of the straight line for the graph drawn between $\ln k$ and $\frac{1}{T}$,where $k$ is the rate constant of a reaction at temperature $T$?

In the Arrhenius equation,the fraction of molecules having energy equal to or greater than the activation energy at a given temperature is represented by .....