How should vinegar be diluted for lice to 9%? - briefly
To obtain a 9 % acetic‑acid solution, combine one part 20 % white vinegar with roughly 1.22 parts water, yielding the desired concentration. Apply the mixture to the scalp, leave for about 10 minutes, then rinse thoroughly.
How should vinegar be diluted for lice to 9%? - in detail
To obtain a solution containing 9 % acetic acid, begin with a vinegar whose concentration is known. Commercial white distilled vinegar typically contains 5 % acetic acid; stronger varieties, such as cleaning vinegar, may be 6 % or 10 %. If the starting material is weaker than 9 %, it cannot be used alone; a higher‑strength vinegar (e.g., 12 % or 15 %) is required.
Calculation example (using 12 % vinegar):
- Desired final volume: V_f
- Desired concentration: 9 %
- Initial concentration: C_i = 12 %
The volume of undiluted vinegar needed (V_i) is determined by the proportion
V_i = (C_f / C_i) × V_f = (9 / 12) × V_f = 0.75 × V_f.
The remaining portion (V_w) is water:
V_w = V_f – V_i = 0.25 × V_f.
Thus, mix three parts of 12 % vinegar with one part of distilled water to achieve a 9 % solution.
Procedure:
- Measure the required volume of the high‑strength vinegar using a calibrated container.
- Add the calculated volume of potable water (preferably distilled or boiled and cooled) to the vinegar.
- Stir gently until homogeneous.
- Transfer the mixture to a clean, airtight bottle; label with concentration and date.
Application guidelines for lice:
- Apply the 9 % solution to dry hair, ensuring full coverage of the scalp and hair shafts.
- Allow the liquid to remain for 10–15 minutes; the acidic environment disrupts the lice exoskeleton.
- Rinse thoroughly with lukewarm water; follow with a regular shampoo if desired.
- Repeat the treatment after 7 days to address newly hatched nymphs.
Safety considerations:
- Conduct a patch test on a small skin area 24 hours before full application to detect possible irritation.
- Avoid contact with eyes and mucous membranes; in case of accidental exposure, rinse with plenty of water.
- Store the solution away from children and pets; keep at room temperature, away from direct sunlight.
If a 12 % or higher‑strength vinegar is unavailable, concentrate the desired volume by evaporating water under controlled conditions, then recombine according to the same proportion formula. This ensures the final product consistently reaches the target 9 % acetic acid concentration.