Final answer:
To prepare 0.5 M HCl from an 11.9 M stock solution, measure out approximately 10.5 mL of stock solution and dilute with water to achieve a final volume of 250 mL.
Step-by-step explanation:
To prepare 0.5 M of HCl in 250 mL from an 11.9 M stock solution, you can use the dilution formula: C1V1 = C2V2. In this formula, C1 and V1 are the concentration and volume of the stock solution, respectively, whereas C2 and V2 are the concentration and volume of the desired solution, respectively. Plugging in the values we have:
C1 = 11.9 M (stock solution)
C2 = 0.5 M (desired solution)
V2 = 250 mL (desired volume)
V1 = ? (volume of stock solution needed)
Using the formula:
V1 = (C2 * V2) / C1
V1 = (0.5 M * 250 mL) / 11.9 M
V1 ≈ 10.5 mL
You would need to measure out approximately 10.5 mL of the 11.9 M stock HCl solution and then add enough water to reach a final volume of 250 mL to obtain a 0.5 M HCl solution.