Final answer:
The Cl⁻ concentration in Ringer's solution must be 160 mEq/L to maintain charge balance with the sum of the cation concentrations Na⁺, K⁺, and Ca²⁺.
Step-by-step explanation:
The Cl⁻ concentration in the Ringer's solution in milliequivalents per liter (mEq/L) would be 156 mEq/L.
To achieve electrical neutrality, the concentration of Cl⁻ ions in Ringer's solution must be equal to the sum of the concentrations of the positively charged cations. Therefore, the total concentration of Cl⁻ should be 151 mEq/L (147 mEq/L Na⁺ + 5 mEq/L K⁺ + (2 x 4 mEq/L Ca²⁺)).
In Ringer's solution, the concentration of each cation is expressed in milliequivalents per liter (mEq/L), which takes into account both the molarity and the charge of the ions. Because Na⁺ and K⁺ each carry a +1 charge, their concentrations can be summed directly. However, Ca²⁺ carries a +2 charge, so its mEq/L value is twice the molarity.
To maintain electrical neutrality, the total positive charge must equal the total negative charge, thus we add the mEq/L of the cations to find the required Cl⁻ concentration. Given that Na⁺ concentration is 147 mEq/L, K⁺ is 5 mEq/L, and Ca²⁺ is 4 mEq/L (which is 8 mEq/L when considering the charge), the total positive charge sums up to 160 mEq/L. Since Cl⁻ is the only anion present, its concentration must also be 160 mEq/L to balance the charges.