C6H12O6->2C2H5OH+2СО2
n(C6H12O6)=72/180=0,4моль
n(C6H12O6)=2n(C2H5OH)
n(C2H5OH)=0,8моль
m(C2H5OH)=0.8*46=36,8г
36,8-100
30,8-х
х=83,7%
