For a reaction,$K = 4.5 \times 10^{-4} \ L \ mol^{-1} \ s^{-1}$. What is the order of the reaction?

The unit of rate constant $K$ for a third-order reaction is . . . . . . .

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

Reaction : $2Br^{-} + H_2O_2 + 2H^{+} \to Br_2 + 2H_2O$
takes place in two steps :
$(a)$ $Br^{-} + H^{+} + H_2O_2 \xrightarrow{slow} HOBr + H_2O$
$(b)$ $HOBr + Br^{-} + H^{+} \xrightarrow{fast} H_2O + Br_2$
The order of the reaction is

For an elementary reaction,which of the following is correct?

For the reaction $2H_2 + 2NO \to N_2 + 2H_2O$,the following mechanism has been proposed:
$I$. $2NO \rightleftharpoons N_2O_2$ (fast)
$II$. $N_2O_2 + H_2 \xrightarrow{k_2} N_2O + H_2O$ (slow)
$III$. $N_2O + H_2 \to N_2 + H_2O$ (fast)
What will be the rate law of this reaction?