Answer
168$^{\circ}$C
Work Step by Step
$T_{1}= (-18+273)K= 255\,K$
$P_{1}= 0.950\,atm= 0.950\,atm\times\frac{760\,torr}{1\,atm}$
$=722\,torr$
$P_{2}=1250\,torr$
According to Gay Lussac's law, if n and V are constant
$\frac{P_{1}}{T_{1}}=\frac{P_{2}}{T_{2}}$
$\implies T_{2}=\frac{P_{2}T_{1}}{P_{1}}=\frac{1250\,torr\times255\,K}{722\,torr}=441\,K$
$=(441-273)^{\circ}C=168^{\circ} C$
