Question

Assume that you have 1 M stock solution of NaCl, KCl, and CaCl2. If the ion concentrations in human plasma are 120 mM Na+, 12 mM K+, and 2 mM Ca2+, calculate the volumes in ml of the stock solutions and distilled water that must be mixed to prepare 1 L of Ringer’s solution that contains the same concentrations of these cations as does human plasma.

Na+ =
K+ =
Ca2+ =
H2O =

Answer 1

To prepare 1 L of Ringer’s solution with ion concentrations similar to human plasma, add 120 mL of 1 M NaCl, 12 mL of 1 M KCl, and 0.67 mL of 1 M CaCl2 to distilled water up to 1 L.

Step-by-step explanation:

To prepare 1 L of Ringer’s solution with plasma-like ion concentrations using 1 M stock solutions of NaCl, KCl, and CaCl2, you need to calculate the volume of each stock solution to add based on the desired concentration of ions in the final solution. The desired concentrations are 120 mM Na+, 12 mM K+, and 2 mM Ca2+. The amount (in moles) of each ion needed for 1 L is calculated by multiplying the target concentration by the volume of the final solution. For NaCl, 0.12 mol is needed since the desired concentration is 120 mM; likewise, 0.012 mol of K+ from KCl and 0.002 mol of Ca2+ from CaCl2 are required.

Applying the dilution formula (C1V1 = C2V2), we find the volumes of the stock solutions to add: 120 mL of NaCl, 12 mL of KCl, and 0.67 mL of CaCl2 (since it provides 2 mol of Ca2+ ions per 1 L). The volumes for the stock solutions are then subtracted from 1 L to determine the amount of distilled water needed to reach the final volume of 1 L.

Add 120 mL of NaCl, 12 mL of KCl, and 0.67 mL of CaCl2 stock solutions to distilled water to make 1 L of Ringer’s solution.