Which of the following is used for preservation of alcohol?: (A) Potassium acetate, (B) Sodium sulphide, (C) Sodium fluoride, (D) Glycerine
Answer is C. (Sodium fluoride)

Sodium fluoride is a useful preservative in a suspected case of alcohol poisoning.
It is done with mixing 10 mL of blood with potassium oxalate & sodium fluoride (enzyme inhibitors)
for suspected alcohol poisoning.
A preservative (sodium fluoride, 0.5 -2% weight by volume) should be added after collecting a vitreous humour sample for ethanol analysis in postmortem toxicology cases.
Gastric contents can be stored in saturated salt solution.