NIC Esthetician Written ExamSafety and Infection ControlHard
An esthetician is preparing a disinfectant solution. The concentrate requires a 1:10 dilution ratio. If the disinfectant container holds 1000 mL, how much disinfectant concentrate is needed?
- A50 mL
- B100 mL
- C200 mL
- D10 mL
Show answer & explanationAnswer & explanation
Correct answer: B. 100 mL
A 1:10 dilution means 1 part concentrate to 10 total parts. So, for a 1000 mL container, you divide the total volume by 10 to find the amount of concentrate needed: 1000 mL / 10 = 100 mL.
Why the other options are wrong
- A. 50 mL would be a 1:20 dilution for a 1000mL container, which is too weak.
- C. 200 mL would be a 1:5 dilution for a 1000mL container, which is too strong and wasteful.
- D. 10 mL would be a 1:100 dilution for a 1000mL container, which is too weak.
Disinfectant Dilution Calculation
To calculate the amount of concentrate needed for a specific dilution ratio (e.g., 1:X), divide the total volume of the solution by X. This yields the amount of concentrate, with the remainder being water.
- Ratio X means 1 part concentrate to X total parts solution.
- Formula: Total Volume / Ratio = Concentrate Volume.
- Accurate dilution ensures efficacy and safety.
Memory trick: Divide Total by Ratio to Get Concentrate.