For an elementary reaction,$2A + B \to C + D$,the molecularity is:

........ of a reaction cannot be determined experimentally.

The reaction $2 \ NO + Br_2 \rightarrow 2 \ NOBr$ takes place through the mechanism given below:
$NO + Br_2 \Leftrightarrow NOBr_2$ (fast)
$NOBr_2 + NO \rightarrow 2 \ NOBr$ (slow)
The overall order of the reaction is $.....$.

$A$ reaction $A + B \rightarrow C$ is second order in $A$ and zeroth order in $B$. How is the rate affected when the concentration of $A$ is doubled and $B$ is halved?

The rate law for the reaction $A + B \rightarrow P$ is given by $\text{rate} = k[A]^2[B]$. The rate constant of the reaction at $300 \text{ K}$ is $6.0 \text{ M}^{-2} \text{s}^{-1}$. Calculate the rate of the reaction when $[A] = 1 \text{ M}$ and $[B] = 0.2 \text{ M}$. (in $\text{ M s}^{-1}$)

For the reaction $NH_4^+ + NO_2^- \to N_2 + 2H_2O$,the experimental data is given below. Determine the rate law for the reaction.

$1.$ $[NH_4^+] = 0.24 \, M, [NO_2^-] = 0.10 \, M, \text{Rate} = 7.2 \times 10^{-6} \, M/s$

$2.$ $[NH_4^+] = 0.12 \, M, [NO_2^-] = 0.10 \, M, \text{Rate} = 3.6 \times 10^{-6} \, M/s$

$3.$ $[NH_4^+] = 0.12 \, M, [NO_2^-] = 0.15 \, M, \text{Rate} = 5.4 \times 10^{-6} \, M/s$