This shows H: O: C: = 2 : 1 :1
That is empirical formula no. of oxygen atoms = no. of carbon atoms and number of hydrogen atoms is twice the number of oxygen atoms
∴ 2 x oxygen atoms = hydrogen atoms
H = 2 x 12 = 24
Oxygen atoms = carbon atoms = 12 (given)
∴ Empirical formula = C12 H24 O12.