The half-life of a reaction is found to be inversely proportional to the cube of its initial concentration. The order of the reaction is:

For the reaction, $A + B \rightarrow P$, the rate law is $\text{rate} = k[A][B]^2$. The rate of reaction is $0.25 \text{ Ms}^{-1}$ when $[A] = 1 \text{ M}$ and $[B] = 0.2 \text{ M}$ at $25^\circ \text{C}$. Calculate the rate constant $k$ of the reaction at the same temperature.

What is the order of reaction $A + B \to C$?

Observation	$[A] \ (mol \ L^{-1})$	$[B] \ (mol \ L^{-1})$	Rate $(mol \ L^{-1} \ sec^{-1})$
$1$	$0.1$	$0.1$	$2 \times 10^{-3}$
$2$	$0.4$	$0.1$	$3.2 \times 10^{-3}$
$3$	$0.1$	$0.2$	$8 \times 10^{-3}$

Which of the following statements is true regarding the order of a reaction?

Consider the following reaction $A + B \rightarrow C$.
The time taken for $A$ to become $1/4$ of its initial concentration is twice the time taken to become $1/2$ of the same. Also,when the change of concentration of $B$ is plotted against time,the resulting graph gives a straight line with a negative slope and a positive intercept on the concentration axis. The overall order of the reaction is . . . . .

At what concentration of the reactant (in $M$) are the rate constants for first-order,second-order,and third-order reactions equal?