Here's how to find it:

1. Molecular Formula: The molecular formula of lactic acid is C₃H₆O₃.

2. Simplest Ratio: To find the empirical formula, you need to determine the simplest whole-number ratio of atoms in the molecule.

3. Divide by Common Factor: The greatest common factor of 3, 6, and 3 is 3. Divide each subscript in the molecular formula by 3:

* C₃ / 3 = C₁

* H₆ / 3 = H₂

* O₃ / 3 = O₁

Therefore, the empirical formula of lactic acid is CH₂O.