What is the value in mg/dL for a solution containing 10 mg of CaCl2 made with 100 mL of distilled water?

• A. 10
• B. 100
• C. 50
• D. Cannot determine without additional information

Answer: (A)

mg/dL tells you how many milligrams of solute are present in each deciliter of solution. Here you have 10 mg of CaCl2 in 100 mL of solution. Since 1 deciliter equals 100 milliliters, that 100 mL is 1 dL. Therefore the concentration is 10 mg per 1 dL, which is 10 mg/dL. No additional information is needed.