Answer :

First we need to know at standart conditions:

P = 1 atm

T = 273.15 K

R = 0.082 atm.L/K.mol

The question gives us:

n = 4 moles of hydrogen

We can use the following formula: PV = nRT

1 x V = 4 x 273.15 x 0.082

V = 89.6 L

Answer: V = 89.6 L