From the rate expression for the following reactions, determine their order of reaction and the dimensions of the rate constants.
(i) 3 NO(g) → N2O (g) Rate = k[NO]2
(ii) H2O2 (aq) + 3 I− (aq) + 2 H+ → 2 H2O (l) + 
Rate = k[H2O2][I−]
(iii) CH3CHO(g) → CH4(g) + CO(g) Rate = k [CH3CHO]3/2
(iv) C2H5Cl(g) → C2H4(g) + HCl(g) Rate = k [C2H5Cl]
(i) Given rate = k [NO]2
Therefore, order of the reaction = 2
Dimension of $k=\frac{\text { Rate }}{[\mathrm{NO}]^{2}}$
$=\frac{\mathrm{mol} \mathrm{L}^{-1} \mathrm{~s}^{-1}}{\left(\mathrm{~mol} \mathrm{~L}^{-1}\right)^{2}}$
$=\frac{\mathrm{mol} \mathrm{L}^{-1} \mathrm{~s}^{-1}}{\mathrm{~mol}^{2} \mathrm{~L}^{-2}}$
$=\mathrm{L} \mathrm{mol}^{-1} \mathrm{~s}^{-1}$
(ii) Given rate = k [H2O2] [I−]
Therefore, order of the reaction = 2
Dimension of $k=\frac{\text { Rate }}{\left[\mathrm{H}_{2} \mathrm{O}_{2}\right]\left[\mathrm{I}^{-}\right]}$
$=\frac{\mathrm{mol} \mathrm{L}^{-1} \mathrm{~s}^{-1}}{\left(\mathrm{~mol} \mathrm{~L}^{-1}\right)\left(\mathrm{mol} \mathrm{L}^{-1}\right)}$
$=\mathrm{L} \mathrm{mol}^{-1} \mathrm{~s}^{-1}$
(iii) Given rate = k [CH3CHO]3/2
Therefore, order of reaction $=\frac{3}{2}$
Dimension of $k=\frac{\text { Rate }}{\left[\mathrm{CH}_{3} \mathrm{CHO}\right]^{\frac{3}{2}}}$
$=\frac{\mathrm{mol} \mathrm{L}^{-1} \mathrm{~s}^{-1}}{\left(\mathrm{~mol} \mathrm{~L}^{-1}\right)^{\frac{3}{2}}}$
$=\frac{\mathrm{mol} \mathrm{L}^{-1} \mathrm{~s}^{-1}}{\mathrm{~mol}^{\frac{3}{2}} \mathrm{~L}^{-\frac{3}{2}}}$
$=L^{\frac{1}{2}} \mathrm{~mol}^{-\frac{1}{2}} \mathrm{~s}^{-1}$
(iv) Given rate = k [C2H5Cl]
Therefore, order of the reaction = 1
Dimension of $k=\frac{\text { Rate }}{\left[\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{Cl}\right]}$
$=\frac{\operatorname{mol} L^{-1} s^{-1}}{\operatorname{mol} L^{-1}}$
$=\mathrm{s}^{-1}$