Explanation:
It'd be better to use cyclohexane. The possible explanation is that the freezing temperature will change by 20.1 degrees for each mole of substance added to 1 kg of cyclohexane, although the same amount added to naphthalene will change its freezing point just by 6.94 degrees.
It is so much easier to identify a larger change more adequately than a smaller one. You would actually not have a 1 molal solution in operation, so the variations in freezing points would be even smaller than the ones already described.
