Final answer:
The empirical van't Hoff's rule involves the van't Hoff factor which expresses the ratio between the actual number of particles in a solution and the expected number based on the stoichiometry of the dissolved substance, mainly accurate for dilute solutions. Higher concentrations exhibit deviations due to ionic interactions, resulting in lower than expected van't Hoff factors.
Step-by-step explanation:
The empirical van't Hoff's rule relates to the colligative properties of solutions, particularly dealing with the number of particles formed in a solution from a dissolved substance.
The van't Hoff factor (i) is an essential concept within this rule and is defined as the ratio of solute particles in solution to the number of formula units dissolved, helping to calculate the effects of ionization on properties such as boiling point elevation and freezing point depression.
However, the ideal van't Hoff factor holds true mainly for dilute solutions (less than 0.001 M). Above that concentration, the actual number of particles in solution tends to be less than expected due to interactions between ions of opposite charge, thus resulting in lower van't Hoff factors and reflecting a deviation from ideal behavior.