Final answer:
Calcium would have a lower milliequivalent than potassium with an equal milligram percent in solution because calcium's valency of +2 leads to half the milliequivalents compared to the monovalent potassium.
Step-by-step explanation:
With an equal milligram percent in solution, calcium would have a lower milliequivalent than potassium. This is because the milliequivalent of an ion depends on both its milligram percent (concentration) and its valency. Potassium, with a charge of +1 (monovalent), has a milliequivalent equal to its millimole value.
Calcium, with a charge of +2 (divalent), has a milliequivalent equal to half its millimole value. Therefore, for the same mass percent in solution, calcium's valency of +2 leads to half the number of milliequivalents when compared to potassium's milliequivalents, which is based on a valency of +1.