The rate of reaction is determined by the slow step of the reaction. This step is called:

The reaction,$X + 2Y + Z \to N$ occurs by the following mechanism:
$(i)$ $X + Y \rightleftharpoons M$ (very rapid equilibrium)
$(ii)$ $M + Z \to P$ (slow)
$(iii)$ $P + Y \to N$ (very fast)
What is the rate law for this reaction?

The rate of reaction,$A + B \rightarrow \text{product}$,is $7.2 \times 10^{-2} \ mol \ dm^{-3} \ s^{-1}$ at $[A] = 0.4 \ mol \ dm^{-3}$ and $[B] = 0.1 \ mol \ dm^{-3}$. The reaction is first order in $A$ and second order in $B$. Calculate the rate constant.

What is the molecularity of the following reactions?
$1.$ $NH_4NO_2(s) \rightarrow N_2(g) + 2H_2O(l)$
$2.$ $2HI(g) \rightarrow H_2(g) + I_2(g)$
$3.$ $2NO(g) + O_2(g) \rightarrow 2NO_2(g)$

For the reaction $H_{2(g)} + Br_{2(g)} \rightarrow 2HBr_{(g)}$,the experimental data suggests the rate law is $\text{Rate} = K[H_2][Br_2]^{1/2}$. Find the order of the reaction and its molecularity.

The rate constants for first-order and second-order reactions have units of ..... respectively.