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

At $100°\mathrm{C}$ the gas reaction $\mathrm{A}⟶2 \mathrm{B}+\mathrm{C}$ was observed to be of first order. On starting with pure $\mathrm{A}$ it is found that at the end of $10$ minutes the total pressure of system is $176 \mathrm{mm}.\mathrm{Hg}$ and after a long time 270 $\mathrm{mmHg}$. From these data find initial pressure of $\mathrm{A}$.

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

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

Decomposition of reaction $3 \mathrm{A}\left(\mathrm{g}\right)⟶2 \mathrm{B}\left(\mathrm{g}\right)+2\mathrm{C}\left(\mathrm{g}\right)$ follows first order kinetics. Starting with pure '$\mathrm{A}$' pressure developed after $20 \min$ and infinite time are $3.5$ and $4 \mathrm{atm}$ respectively.

What is time taken for $75\%$ decomposition of $\text{A}$?

Two substance $A$($t_{1/2}=5$ mins$)$ and $B$($t_{1/2}=15$ mins) follow first order kinetics are taken in such a way that initially $\left[\mathrm{A}\right]=4[ \mathrm{B}]$. Calculate the time after which the concentration of both the substance will be equal.

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

For each question, enter the correct numerical value (in decimal notation, truncated/rounded off to the second decimal place; e.g. $6.25, 7.00, -0.33, -.30, 30.27, -127.30$, if answer is 11.36777..... then both $11.36777$..... then both $11.36$ and $11.37$ will be correct) by darken the corresponding bubbles in the ORS.