Final answer:
Karen should use 24 ml of the 12.5% povidone-iodine solution and add 126 ml of water to prepare 150 ml of a 2% solution for surgical disinfection.
Step-by-step explanation:
The task involves preparing a diluted povidone-iodine solution with a specific concentration for surgical disinfection. To do this, we need to apply a standard dilution formula, which is (Concentration1) x (Volume1) = (Concentration2) x (Volume2), often abbreviated to C1V1 = C2V2, where:
- C1 is the initial concentration of the solution (12.5%)
- V1 is the volume of the initial solution we need to find
- C2 is the final concentration of the solution (2%)
- V2 is the final volume of the diluted solution (150 ml)
Using this formula, we can solve for V1:
(12.5%) x V1 = (2%)(150 ml)
V1 = (2%)(150 ml) / (12.5%)
V1 = 24 ml
Karen should start with 24 ml of the 12.5% povidone-iodine. To find out how much water she needs, we subtract the volume of povidone-iodine from the total required volume of the solution.
150 ml - 24 ml = 126 ml
Karen will need 126 ml of water to prepare the 150 ml of 2% povidone-iodine solution.