NIC Nail Technician Written ExamScientific ConceptsMedium
A technician is preparing a 0.25% solution of a disinfectant. If the disinfectant concentrate is 25% active ingredient, and the technician needs to prepare 1 gallon (128 fl oz) of the solution, how much of the concentrate is needed?
- A0.512 fl oz
- B5.12 fl oz
- C0.128 fl oz
- D1.28 fl oz
Show answer & explanationAnswer & explanation
Correct answer: D. 1.28 fl oz
To calculate the amount of concentrate needed, use the formula: (Desired Concentration / Concentrate's Active Ingredient Percentage) * Total Volume. So, (0.25% / 25%) * 128 fl oz = (0.0025 / 0.25) * 128 fl oz = 0.01 * 128 fl oz = 1.28 fl oz.
Why the other options are wrong
- A. Incorrect calculation; this might result from an error in percentage conversion or division.
- B. Incorrect calculation; this would be if the desired concentration was 2.5% or a similar error.
- C. Incorrect calculation; this would be 0.1% of the total volume, not accounting for concentrate strength.
Disinfectant Dilution Calculation (Concentrate)
Calculating the amount of concentrated disinfectant needed to achieve a specific final solution percentage, considering the active ingredient percentage of the concentrate.
- Formula: (Desired Solution % / Concentrate Active Ingredient %) * Total Volume.
- Ensure all percentages are converted to decimals for calculation.
- Accuracy is crucial for effective disinfection and safety.
Memory trick: Divide the desired by the concentrate, then multiply by the total volume.