Carbon monoxide, CO, and hydrogen, H2, react according to the reaction below.

4 CO(g)+ 9 H2(g)--> C4H10(g)+ 4 H2O(g)

What volume of the excess reactant remains if 19.6 L CO and 27.2 L H2 are allowed to react. Assume that the volumes of both gases are measured at 713oC and 1.35 atm.
Give your answer in litres, accurate to two significant figures. Do not include the units as part of your answer.