The rate constant for the reaction $H_2 + I_2 \to 2HI$ is $k_1 = 49$. What is the rate constant for the reverse reaction $2HI \to H_2 + I_2$?

Half-lives of a first-order and a zero-order reaction are the same. Assume that the initial concentration of the reactant is the same for both reactions,then the ratio of the initial rates of the first-order reaction to that of the zero-order reaction is:

The effect of $pH$ on the rate constant for the hydrolysis of an ester is given by:

Given below are two statements:
Statement $I$: The rate law for the reaction $A + B \rightarrow C$ is rate $(r) = k[A]^2[B]$. When the concentration of both $A$ and $B$ is doubled,the reaction rate is increased "$x$" times.
Statement $II$: The figure shows the variation in concentration against time plot for a "$y$" order reaction.
Concentration of $R$ vs Time plot: $A$ straight line with a negative slope equal to $-K$.
The value of $x + y$ is . . . . . .

The following graph shows the variation of rate constant $(k)$ with temperature $(T)$. Which graph follows the Arrhenius equation?

For any chemical reaction,what factors do chemists aim to determine?