2 dm³
4 dm³
8 dm³
3 dm³
The combined gas law or general gas equation is obtained by combining Boyle's Law, Charles' Law, and Gay-Lussac's Law. It shows the relationship between the pressure, volume, and temperature for a fixed mass (quantity) of gas.
∵p₁V₁/T₁ = p₂V₂/T₂
p₁×4/T₁ = 2p₁×V₂/2T₁
2V₂ = 8
V₂ = 4 dm³
Option C is correct.