Question

You have a concentrated stock solution of 10 M NaOH and want to use it to produce a 150 ml solution of 3 M NaOH. What volume of water and stock solutions will you measure out to make this new solution?

1) 135 ml of water, 15 ml of NaOH stock
2) 115 ml of water, 35 ml of NaOH stock
3) 100 ml of water, 50 ml of NaOH stock
4) 105 ml of water, 45 ml of NaOH stock

Answer 1

To prepare a 3 M NaOH solution from a 10 M NaOH stock solution, 45 mL of the stock solution should be diluted with 105 mL of water to achieve the desired final volume of 150 mL. Option 4.

Step-by-step explanation:

To calculate the volume of concentrated stock solution and water needed to prepare a 3 M NaOH solution from a 10 M NaOH stock solution, we use the dilution formula M1V1 = M2V2, where M1 is the concentration of the stock solution, V1 is the volume of the stock solution needed, M2 is the desired concentration, and V2 is the final volume of the diluted solution.

Here, M1 = 10 M, M2 = 3 M and V2 = 150 mL. Plugging the values into the equation, we get 10 M * V1 = 3 M * 150 mL. Solving for V1 gives us V1 = (3 M * 150 mL) / (10 M) = 45 mL. This is the volume of stock solution needed.

The rest of the volume up to 150 mL will be water, so the volume of water needed is 150 mL - 45 mL = 105 mL. Therefore, you need 45 mL of 10 M NaOH stock solution and 105 mL of water to make a 150 mL solution of 3 M NaOH. Option 4.