Question

Side A: 7% glucose 5% salt
Side B: 5% glucose 7% salt
What will the concentration of salt be on each side when it becomes isotonic for salt?
Salt = ___ %

Answer 1

6%

Assuming equal volumes on both sides, salt diffuses until concentrations equal. Total salt = 5 + 7 = 12 (per 2 volume units), so each side ends up with 12/2 = 6% salt.