Answer
$1365^{\circ}$C
Work Step by Step
$T_{1}= (0+273)K= 273\,K$
$P_{1}= 250\,torr$
$P_{2}=1500\,torr$
According to Gay Lussac's law, if n and V are constant
$\frac{P_{1}}{T_{1}}=\frac{P_{2}}{T_{2}}$
$\implies T_{2}=\frac{P_{2}T_{1}}{P_{1}}=\frac{1500\,torr\times273\,K}{250\,torr}=1638\,K$
$=(1638-273)^{\circ}C=1365^{\circ} C$
