Which solubility expression represents the amount of solvent needed to dissolve one gram of solute?

• A. g in 1 mL
• B. g in 100 mL
• C. mL per 1 g
• D. mL per 100 g

Answer: (C)

Solubility can be expressed either as how much solute dissolves in a given amount of solvent or as how much solvent is required to dissolve a given amount of solute. When the question asks for the amount of solvent needed to dissolve one gram of solute, the relevant expression is the solvent-per-gram form: milliliters of solvent per 1 gram of solute. This directly shows how much solvent is needed for each gram of solute, which is why it’s the best fit. The other formats specify grams of solute per a fixed amount of solvent (g in 1 mL, g in 100 mL) or solvent per a fixed amount of solute (mL per 100 g), which don’t answer the requested “solvent per 1 g” relationship.