How many ml of water should be added to 20.0 ml of a stock of 12.0 M HCl solution to make 1.50 M HCl ?assume that the volumes are additive.

To find out how much water should be added, we need to use the concept of dilution. Dilution is performed by adding a solvent (in this case, water) to a concentrated solution to reduce its concentration.

Here's the formula we can use to calculate the volume of water (V_water) to be added:

C1 * V1 = C2 * V2

Where:
C1 = initial concentration of the stock solution
V1 = initial volume of the stock solution
C2 = final concentration of the diluted solution
V2 = final volume of the diluted solution (V_water + V_stock)

In this scenario, the initial concentration (C1) is 12.0 M, the initial volume (V1) is 20.0 ml, the final concentration (C2) is 1.50 M, and we need to find the final volume (V2).

Let's plug the values into the formula and solve for V_water:

12.0 M * 20.0 ml = 1.50 M * V2

240 ml = 1.50 M * V2

Now, rearrange the equation and solve for V2:

V2 = 240 ml / 1.50 M
V2 = 160 ml

Therefore, to make a 1.50 M HCl solution, you should add 160 ml of water to the 20.0 ml of the 12.0 M HCl stock solution.