For a reaction,$A + 2B \rightarrow$ Products,when the concentration of $B$ alone is increased,the half-life remains the same. If the concentration of $A$ alone is doubled,the rate remains the same. The unit of the rate constant for the reaction is:

The rate constant for the reaction $2N_2O_5 \rightarrow 4NO_2 + O_2$ is $3.0 \times 10^{-5} \text{ s}^{-1}$. If the rate of reaction is $2.4 \times 10^{-5} \text{ mol L}^{-1} \text{ s}^{-1}$, then the concentration of $N_2O_5$ in $\text{mol L}^{-1}$ is:

$2 \ NO_{(g)} + Cl_{2(g)} \rightleftharpoons 2 \ NOCl_{(g)}$
This reaction was studied at $-10^{\circ} C$ and the following data was obtained:

$Run$	$[NO]_{0}$	$[Cl_{2}]_{0}$	$r_{0}$
$1$	$0.10$	$0.10$	$0.18$
$2$	$0.10$	$0.20$	$0.35$
$3$	$0.20$	$0.20$	$1.40$

$[NO]_{0}$ and $[Cl_{2}]_{0}$ are the initial concentrations and $r_{0}$ is the initial reaction rate.
The overall order of the reaction is ..........
(Round off to the Nearest Integer).

By giving three examples,explain whether the exponents of the concentration terms in a rate law are the same as their stoichiometric coefficients in the balanced chemical reaction.

$t_{1/2} =$ constant confirms the first order reaction. If $a^2 t_{1/2} =$ constant,it confirms that the order of reaction is ($a =$ initial concentration of reactant).

Consider the reaction:
$Cl_{2(aq)} + H_2S_{(aq)} \rightarrow S_{(s)} + 2H^{+}_{(aq)} + 2Cl^{-}_{(aq)}$
The rate equation for this reaction is:
$\text{rate} = k[Cl_2][H_2S]$
Which of these mechanisms is/are consistent with this rate equation?
$A.$ $Cl_2 + H_2S \rightarrow H^{+} + Cl^{-} + Cl^{+} + HS^{-}$ (slow)
$Cl^{+} + HS^{-} \rightarrow H^{+} + Cl^{-} + S$ (fast)
$B.$ $H_2S \rightleftharpoons H^{+} + HS^{-}$ (fast equilibrium)
$Cl_2 + HS^{-} \rightarrow 2Cl^{-} + H^{+} + S$ (slow)