Question

One litre of $O_2$ and one litre of $H_2$ are taken in a vessel of 2 litre capacity at NTP. The gases are made to combine to form water. Calculate the total pressure (in atm as nearest integer), if the vessel is heated to ${100}^{o}C$.

Answer 1

$\underset{\underset{\text{Volume after reaction (litre)}}{\text{Volume before reaction (in litre)}}}{\text{The given reaction is}}\underset{\underset{0}{1}}{2H_2+}\underset{\underset{0.5}{1}}{O_2}\underset{\underset{1}{0}}{\to 2H_{2}O}$
On heating to ${100}^{o}C,H_{2}O$ exists as vapours
$\therefore$ Total mole present at ${100}^{o}c$
$=moleof{H}_{2}O+moleof{O}_2$
$=4.46\times {10}^{-2}+2.23\times {10}^{-2}$
$=6.69\times {10}^{-2}K$
Volume of vessel $=2litre,T=373K$
$P=\frac{nRT}{V}=\frac{6.69\times {10}^{-2}\times 0.0821\times 393}{2}$
$=1.07atm$