Select incorrect statement (s):

A drug is known to be ineffective after it has decomposed $30\%$. The original concentration of a sample was $500 \mathrm{units}/\mathrm{mL}$. when analyzed $20$ months later, the concentration was found to be $420 \mathrm{units}/\mathrm{mL}$. Assuming that decomposition is of $\mathrm{I}$ order, what will be the expiry time of the drug?

Fill your answer as sum of digits till you get the single digit answer.

The following data were obtained in experiment on inversion of cane sugar

Time (minutes) $\begin{array}{cccc}0& 60& 120& 180\end{array} \infty$

Angle of rotation (degree) $\begin{array}{cccc}+13.1& +11.6& +10.2& +9.0\end{array} -3.8$

Show that the reaction is of first order. After what time would you expect a zero reading in polarimeter?

Fill your answer as sum of digits till you get the single digit answer.

The reaction $2\mathrm{NO}+{\mathrm{Br}}_2\to 2\mathrm{NOBr}$, is supposed to follow the following mechanism

(i) $\mathrm{NO}+{\mathrm{Br}}_2\stackrel{\mathrm{fast}}{\rightleftharpoons }{\mathrm{NOBr}}_2$

(ii) ${\mathrm{NOBr}}_2+\mathrm{NO}\stackrel{\mathrm{slow}}{\to }2\mathrm{NObr}$

What is the overall order of reaction?

For the reaction $2{\mathrm{H}}_2+2\mathrm{NO}\to {\mathrm{N}}_2+2{\mathrm{H}}_2\mathrm{O}$, the following mechanism has been suggested:

$2\mathrm{NO}\rightleftharpoons {\mathrm{N}}_2{\mathrm{O}}_2$ equilibrium constant ${\mathrm{k}}_1$ (fast)

${\mathrm{N}}_2{\mathrm{O}}_2+{\mathrm{H}}_2\stackrel{{\mathrm{k}}_2}{\to }{\mathrm{N}}_2\mathrm{O}+{\mathrm{H}}_2\mathrm{O}$ (slow)

${\mathrm{N}}_2\mathrm{O}+{\mathrm{H}}_2\stackrel{{\mathrm{k}}_3}{\to }{\mathrm{N}}_2+{\mathrm{H}}_2\mathrm{O}$ (fast)

What is the overall order reaction?