Final answer:
The empirical formula of the unknown organic compound is CH.
Step-by-step explanation:
The empirical formula of an organic compound can be determined using its combustion analysis. In this case, the unknown compound produced 1.9702 g of CO₂ and 0.7057 g of H₂O when 1.691 g of the compound was combusted. To find the empirical formula, we need to determine the moles of carbon and hydrogen in the compound. The molecular weight of CO₂ is 44 g/mol and the molecular weight of H₂O is 18 g/mol. Therefore, the number of moles of carbon in CO₂ is 1.9702 g / 44 g/mol = 0.0448 mol, and the number of moles of hydrogen in H₂O is 0.7057 g / 18 g/mol = 0.0392 mol. The ratio of carbon to hydrogen is approximately 1.14. Since there is no information about other elements, we assume there are no other elements present in the compound. Therefore, the empirical formula of the unknown compound is CH.