A neutral gas sample contains 84% ( by volume ) of CH4 , 10 % of C2H6 , 3 % of C3H8 and 3% of N2 . If a series of catalytic reacns cud be used for converting all the C atoms of the gas into butadiene , C4H6 , with 100% efficiency , how much butadiene cud be prepared frm 100 g of the natural gas?