Question

Hydrogen peroxide solution was stored in a mild steel vessel. It was found, however, that the hydrogen peroxide decomposed on the walls of the vessel (a first order reaction). An experiment with $100$ ml of a solution gave $10.31$ ml oxygen (corrected to $1$ atm and $273K$) after $5.1$ days. Find how long the peroxide can be stored before the loss of $20.00$ ml oxygen occurs (per $100$ ml solution) under similar storage conditions, if complete decomposition of the sample to $H_2{O}_2$ gave $46.34$ ml oxygen.

• A. $11.45$ days
• B. $12.6$ days
• C. $14.5$ days
• D. $15$ days

Answer 1

The correct option is A $11.45$ days

Complete decomposition gives $46.34ml$ oxygen.
Hence, the volume of hydrogen peroxide present initally is $a=2\times 46.34=92.68ml$

After 5.1 days, 10.31 ml of oxygen are collected

$a-x=92.68-2\left(10.31\right)=72.06ml$

$k=\frac{2.303}{t}log\frac{a}{a-x}=\frac{2.303}{5.1}log\frac{92.68}{72.06}=0.0494/day$

When $20ml$ of oxygen is collected,

$a-x=92.68-2\left(20\right)=52.68ml$

$0.0494=\frac{2.303}{t}log\frac{92.68}{52.68}$

$t=11.45$ days.