CxH2x+2 + O2 → xCO2 + (x+1) H2O

n(CO2) = V/Va = 1 моль

n(CxH2x+2) = n(CO2)/x = 1/x

M(CxH2x+2) = 12*x + 2x + 2 = 14x + 2

m(CxH2x+2) = M * n = 14 + 2/x

14 + 2/x = 14,4

2 = 0,4x

x = 5

C5H12