What volume of oxygen gas is needed for the complete combustion of 4.00 L of ethane gas, C2H6? Assume that the temperature and pressure of the reactants are the same.

Answer 1

2C2H6 + 7O2 ==> 4CO2 + 6H2O

When gases are involved one can take a shortcut and use liters and mols interchangeably.
So 4.00 L C2H6 x (7 mols O2/2 mols C2H6) = 4.00 x 7/2 = ? L O2

Answer 2

Is not there in my options