Answer:
HClO₃
Step-by-step explanation:
Empirical formula of a chemical compound is defined as the simplest ratio of atoms presents in the compound (In whole numbers).
For the H₂Cl₂O₆ the empirical formula could be obtained dividing in 2 the formula. That is:
HClO₃ → This is the simplest ratio of atoms presents in the compound, that is, the empirical formula