Ответ: 2CnH2n+2O+Na->2CnH2n+2Na+H2.
n(H2)=2,8/22,4=0,125моль; n(CnH2n+2O)/n(H2)=2/1=>n(CnH2n+2O)=0,125*2=0,25моль.
M=m/n; M=15/0,25=60. 14n+18=60; n=3
C3H7OH-пропанол