NIC Nail Technician Written ExamScientific ConceptsHard
A technician is preparing a 0.5% solution of a disinfectant. If the disinfectant concentrate is 100% active ingredient and they need to make 2 liters of the solution, how many milliliters of the concentrate are required?
- A20 ml
- B50 ml
- C10 ml
- D5 ml
Show answer & explanationAnswer & explanation
Correct answer: C. 10 ml
To calculate the required concentrate: 0.5% of 2 liters. First, convert 2 liters to milliliters (2 L * 1000 ml/L = 2000 ml). Then, calculate 0.5% of 2000 ml: (0.5 / 100) * 2000 ml = 0.005 * 2000 ml = 10 ml. Therefore, 10 ml of concentrate is needed.
Why the other options are wrong
- A. Incorrect calculation; this would be 1% of 2 liters.
- B. Incorrect calculation; this would be 2.5% of 2 liters.
- D. Incorrect calculation; 0.5% of 1 liter is 5ml, but the target is 2 liters.
Disinfectant Dilution Calculation (Percentage)
Calculating the volume of concentrate needed to achieve a specific percentage solution when the total volume of the solution is known.
- Convert all volumes to the same unit (e.g., ml).
- Formula: (Desired % / 100) * Total Volume = Concentrate Volume.
- Ensure disinfectant is 100% active ingredient for direct calculation.
Memory trick: Percent of Total equals Concentrate.