Answer
21 mL
Work Step by Step
$P_{1}=P_{2}=740.\, mmHg$
$T_{1}=(22.3+273)K=295.3\,K$
$T_{2}= (26.5+273)K=299.5\,K$
$V_{1}=21\,mL$
As the amount of gas and pressure are constant, we can use Charles's law to find the final volume $V_{2}$.
$\frac{V_{1}}{T_{1}}=\frac{V_{2}}{T_{2}}$
$\implies V_{2}=\frac{V_{1}T_{2}}{T_{1}}=\frac{21\,mL\times299.5\, K}{295.3\,K}=21\,mL$
