Question

One litre of $O_2$ and one litre of $H_2$ are taken in a vessel of 2 litre capacity at STP. The gases are made to combine to form water moles of $O_2$ used for the formation of water are $2.23\times {10}^{-x}$, the value of $x$ is.....

Answer 1

$\underset{\underset{\text{Volume after reaction (litre)}}{\text{Volume before reaction (in litre)}}}{\text{The given reaction is}}\underset{\underset{0}{1}}{2H_2+}\underset{\underset{0.5}{1}}{O_2}\underset{\underset{1}{0}}{\to 2H_{2}O}$
Volume of $O_2$ used for formation of $H_{2}O0.5litre$
Mole of $O_2$ used for formation of $H_{2}O$ at NTP
$=\frac{0.5}{22.4}=2.23\times {10}^{-2}$
so value of x is 2.