An unknown organic compound is found on elemental analysis to contain 68.1\(\%\) carbon, 13.7\(\%\) hydrogen, and 18.2\(\%\) oxygen by mass. It is slightly soluble in water. Upon careful oxidation it is converted into a compound that behaves chemically like a ketone and contains 69.7\(\%\) carbon, 11.7\(\%\) hydrogen, and 18.6\(\%\) oxygen by mass. Indicate two or more reasonable structures for the unknown.

Assume we have a 100 g sample of the unknown compound. Then, we can calculate the moles of each element by dividing the mass percentage by their respective molar masses. Carbon: \( \frac{68.1 g}{12.01 g/mol} \approx 5.67 mol \) Hydrogen: \( \frac{13.7 g}{1.008 g/mol} \approx 13.6 mol \) Oxygen: \( \frac{18.2 g}{16.00 g/mol} \approx 1.14 mol \) To find the empirical formula, divide by the smallest number of moles to obtain the mole ratio. Carbon: \( \frac{5.67}{1.14} \approx 5 \) Hydrogen: \( \frac{13.6}{1.14} \approx 12 \) Oxygen: \( \frac{1.14}{1.14} = 1 \) The empirical formula of the unknown organic compound is C5H12O.

Follow the same process as in Step 1 for the oxidized product: Carbon: \( \frac{69.7 g}{12.01 g/mol} \approx 5.81 mol \) Hydrogen: \( \frac{11.7 g}{1.008 g/mol} \approx 11.6 mol \) Oxygen: \( \frac{18.6 g}{16.00 g/mol} \approx 1.16 mol \) Carbon: \( \frac{5.81}{1.16} \approx 5 \) Hydrogen: \( \frac{11.6}{1.16} \approx 10 \) Oxygen: \( \frac{1.16}{1.16} = 1 \) The empirical formula of the oxidized product is C5H10O.

Since the oxidized product behaves like a ketone, the unknown compound must have a functional group that can be oxidized to a ketone. Possibilities include primary and secondary alcohols. - A primary alcohol after oxidation will give an aldehyde, which can be further oxidized to a carboxylic acid, and it deviates from the empirical formula of the oxidized product. Therefore, the primary alcohol option is ruled out. - The unknown compound must be a secondary alcohol, which gives a ketone after oxidation, which matches the given information. Possible reasonable structures for the unknown compound are: 1. 2-pentanol: CH3-CH2-CH(OH)-CH2-CH3 2. 3-methyl-2-butan-2-ol: CH3-C(CH3)(CH3)(OH)-CH3 Both of these structures would produce ketones upon oxidation: 1) Pentan-2-one: CH3-CH2-C(=O)-CH2-CH3 2) 3-methylbutan-2-one: CH3-C(CH3)(=O)-CH2-CH3 These two proposed structures of the unknown organic compound follow the empirical formulas and match the given information about oxidation and solubility.