NIC Nail Technician Written ExamScientific ConceptsHard
A technician is preparing a 2% solution of a disinfectant. If the concentrate is 50% active ingredient and they need to make 1 liter of the 2% solution, how much of the concentrate (in mL) is required?
- A40 mL
- B20 mL
- C100 mL
- D200 mL
Show answer & explanationAnswer & explanation
Correct answer: A. 40 mL
To find the amount of active ingredient needed: 2% of 1000 mL (1 liter) = 20 mL. Since the concentrate is 50% active ingredient, you need to find how much concentrate contains 20 mL of active ingredient: 20 mL / 0.50 = 40 mL. Therefore, 40 mL of the 50% concentrate is needed.
Why the other options are wrong
- B. This would be the amount of active ingredient needed, not the concentrate itself.
- C. This is 10% of the total solution, or double the active ingredient needed.
- D. This is 20% of the total solution, or ten times the active ingredient needed.
Disinfectant Dilution Calculation
Calculating the correct volume of concentrate needed to achieve a desired final concentration in a solution.
- Formula: (Desired % / Concentrate %) * Total Volume.
- Ensure units are consistent (e.g., mL).
- Crucial for efficacy and safety.
Memory trick: Desired concentration, divide by concentrate strength, multiply by total volume.