Answer is: CH2O3

To simplify things, use molar weights and start with it based on 100g

3.25 g of Hydrogen (1 mole H / 1.008 g H) = 3.22

19.36 g of C (1 mole C / 12.01 g C) = 1.61

77.39 g of O (1 mole O / 15.9994 g O) = 4.84

The smallest number needs to be divided into others. In this case, the smallest was 1.61.

So, 1.61/1.61 = 1 . . . So, C = 1.

3.22/1.61 = 2 . . . So, H = 2

4.84/1.61 = 3 . . . So, O = 3

Therefore the empirical formula is equal to: CH2O3