Final answer:
To rank the compounds from least to most soluble in hexane, consider the polarity of the compounds. Ethanoic acid is the least soluble, followed by butanoic acid, then hexanoic acid, and finally octanoic acid, which is the most soluble.
Step-by-step explanation:
To rank the compounds from least to most soluble in hexane, we need to consider the polarity of the compounds. Hexane is a nonpolar solvent, so compounds with nonpolar functional groups will be more soluble in hexane. The more polar functional groups a compound has, the less soluble it will be in hexane.
In this case, we have ethanoic acid, butanoic acid, hexanoic acid, and octanoic acid. These are all carboxylic acids, which have a polar carboxyl group (COOH) attached to a nonpolar alkyl chain. As the alkyl chain gets longer in the carboxylic acid, the solvent solubility in hexane increases. So, from least to most soluble, the ranking would be ethanoic acid, butanoic acid, hexanoic acid, and octanoic acid.