Define the following terms:
$(1)$ Elementary reaction
$(2)$ Complex reaction

For the reaction $A_2 + B_2 \to 2AB$,the experimental data is given below. Determine the order of the reaction.

Experiment No.	$[A_2] \text{ (M)}$	$[B_2] \text{ (M)}$	Rate $(M \cdot s^{-1})$
$1$	$0.1$	$0.1$	$1.6 \times 10^{-4}$
$2$	$0.1$	$0.2$	$3.2 \times 10^{-4}$
$3$	$0.2$	$0.1$	$3.2 \times 10^{-4}$

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

Identify the reaction order for which the rate constant $K = 2.3 \times 10^{-5} \ L \ mol^{-1} \ s^{-1}$.

The order of the reaction occurring by the following mechanism should be:
$(i)$ $A_2 \to A + A$ (fast)
$(ii)$ $A + B_2 \to AB + B$ (slow)
$(iii)$ $A + B \to AB$ (fast)

Consider the kinetic data given in the following table for the reaction $A + B + C \rightarrow$ Product.

Experiment No.	$[A] \ (mol \ dm^{-3})$	$[B] \ (mol \ dm^{-3})$	$[C] \ (mol \ dm^{-3})$	Rate of reaction $(mol \ dm^{-3} \ s^{-1})$
$1$	$0.2$	$0.1$	$0.1$	$6.0 \times 10^{-5}$
$2$	$0.2$	$0.2$	$0.1$	$6.0 \times 10^{-5}$
$3$	$0.2$	$0.1$	$0.2$	$1.2 \times 10^{-4}$
$4$	$0.3$	$0.1$	$0.1$	$9.0 \times 10^{-5}$

The rate of the reaction for $[A]=0.15 \ mol \ dm^{-3}, [B]=0.25 \ mol \ dm^{-3}$ and $[C]=0.15 \ mol \ dm^{-3}$ is found to be $Y \times 10^{-5} \ mol \ dm^{-3} \ s^{-1}$. The value of $Y$ is . . . . . .