How much methane can be formed when coal interacts with 20 liters of hydrogen?

Methane production reaction:
C + 2H2 = CH4.
It can be seen from the reaction equation that 2 mol of hydrogen reacted, and 1 mol of methane was formed.
n (H2) = 2 mol, n (CH4) = 1 mol.
Accordingly, the volume of gas occupied depends on the number of moles:
Vm (H2) = 44.8 L / mol, Vm (CH4) = 22.4 L / mol.
Knowing the volume of hydrogen reacted, we write the expression:
20 l H2 – X l CH4.
44.8 L H2 – 22.4 L CH4.
Let’s find the volume of methane:
V (CH4) = 20 * 22.4 / 44.8 = 10 liters.