Final answer:
You would need 25 mL of 10X PBS stock solution to make 250 mL of 1X PBS, using the dilution equation to calculate the volume needed when the concentration decreases by a factor of 10.
Step-by-step explanation:
To calculate how much 10X PBS stock solution you would need to make 250 mL of 1X PBS, you use the dilution equation (C1V1 = C2V2), where C1 and V1 are the concentration and volume of the stock solution, respectively, and C2 and V2 are the concentration and volume of the final diluted solution, respectively. Since we have a 10X stock and want to make a 1X solution, the concentration is being decreased by a factor of 10. Thus, we aim to find V1 when C1 is 10 times C2.
Applying the dilution equation:
- (10)(V1) = (1)(250 mL)
- V1 = (250 mL) / 10
- V1 = 25 mL
Therefore, 25 mL of the 10X PBS stock solution is required to prepare 250 mL of 1X PBS when the stock solution is diluted with additional solvent to reach the final desired volume. In practices like preparing IV solutions, such accuracy in the concentration of the final solution is quite necessary for medical safety.