Final answer:
The empirical formula is determined by finding the mole ratio of carbon and hydrogen based on their percent composition and adjusting to the simplest whole numbers. However, without molecular weight, the molecular formula cannot be conclusively determined from the options given.
Step-by-step explanation:
To determine the molecular formula of a compound with hydrogen being 17.24% and carbon being 82.76%, we start by calculating the empirical formula. Assuming we have 100 grams of the compound, we would have 17.24 grams of hydrogen and 82.76 grams of carbon. By dividing these masses by the respective atomic weights of hydrogen (1 g/mol) and carbon (12 g/mol), we find the number of moles of each element:
- Hydrogen = 17.24 g ÷ 1 g/mol = 17.24 mol
- Carbon = 82.76 g ÷ 12 g/mol = 6.896 mol
To find the ratio of these moles, we divide each by the smaller number of moles obtained:
- Hydrogen ratio = 17.24 mol / 6.896 mol ≈ 2.5
- Carbon ratio = 6.896 mol / 6.896 mol = 1
The simplest whole number ratio is approximately 2.5:1, but empirical formulas must consist of whole numbers. Since we cannot have half of a hydrogen atom in a formula, we need to multiply both ratios by a factor that will give us whole numbers, in this case 2. This results in a ratio of 2 for carbon and 5 for hydrogen, giving us an empirical formula of C₂H₅.
To find the molecular formula, we would need additional information about the molecular weight of the compound. As we do not have this information, we cannot conclusively determine the molecular formula among the options provided.