Question

How many ml of a 15 M stock is needed to make 5 L of a 0.022 molar NaCl solution?

a) 1.5 mL
b) 150 mL
c) 15 mL
d) 0.15 mL

Answer 1

To make a 0.022 M NaCl solution with a 15 M stock solution, you will need 7.33 mL of the stock solution.

Step-by-step explanation:

To calculate the volume of the stock solution needed to prepare a 0.022 M NaCl solution, we can use the equation (stock concentration) × (stock volume) = (final concentration) × (final volume). Rearranging this equation, we have (stock volume) = (final concentration) × (final volume) / (stock concentration).

In this case, the stock concentration is 15 M, the final concentration is 0.022 M, and the final volume is 5 L. Plugging these values into the equation, we get (stock volume) = (0.022 M) × (5 L) / (15 M).

Simplifying the equation gives us the answer: (stock volume) = 0.00733 L = 7.33 mL.

Therefore, the correct answer is a) 7.33 mL.