If a patient requires 30 mEq of sodium, and the stock solution is 15 mEq per 10 mL, how many mL will be required?

To determine how many milliliters of the stock solution are needed to provide 30 mEq of sodium, you can start by analyzing the concentration of the stock solution. The stock solution has a concentration of 15 mEq per 10 mL.

First, find out how many mEq are in 1 mL of the stock solution. Since 10 mL contains 15 mEq, you can divide the mEq by the volume:

15 mEq / 10 mL = 1.5 mEq/mL.

Next, to find out how many mL are needed to reach a total of 30 mEq, you divide the desired mEq by the concentration in mEq/mL:

30 mEq ÷ 1.5 mEq/mL = 20 mL.

Thus, you need 20 mL of the stock solution to provide the required 30 mEq of sodium, making this choice the correct answer. This calculation ensures that the required dosage is accurately administered for patient care.