Answer:
323.15 °C
Step-by-step explanation:
Considering the ideal gas equation as: 

where, 
P is the pressure 
V is the volume 
n is the number of moles 
T is the temperature 
R is Gas constant having value = 0.0821 L.atm/K.mol
Thus, at constant volume and number of moles, Pressure of the gas is directly proportional to the temperature of the gas.
P ∝ T
Also, 
Using Charle's law 
 
Given , 
P₂ = 2P₁
T₁ = 25 °C 
T₂ = ?
The conversion of T( °C) to T(K) is shown below: 
T(K) = T( °C) + 273.15 
So, 
T₁ = (25 + 273.15) K = 298.15 K 
Using above equation as: 
 
 
New temperature = 596.3 K
Also, 
T(K) - 273.15 = T( °C) 
So, Temperature = 596.3 - 273.15 °C = 323.15 °C