Question

An open flask contains air at ${27}^o$C. The temperature (in $K$) at which it should be heated so that $1/3rd$ of air measured at ${27}^o$C escapes out is ________________. Write the answer in the form of $x$ $\times 100$.

Answer 1

Let initial mole of gas = $n$ at temperature = 300 $K$

The gas on heating to '$T$' $K$, loses ($n/3$ )mole

mole of gas left at temperature ,$T=n-\left(n/3\right)=2n/3$

At constant $PandV$, $n_1{T}_1$=$n_2{T}_2$

$n\times 300=\left(2n/3\right)T$

$T=450K$