The mandelin reagent is naturally a strong yellow colour due to the presence of vanadium oxide, but most of the other reagents are colourless or close to it.
- Mandelin: Strong yellow
- Marquis, Froehde, Liebermann, Mecke: Pure white
- Ehrlich, Hofmann: Slight yellow
- Morris: Slight pink
If your reagents are showing another colour, especially dark colours like green or black, it suggests that they have been contaminated or have expired. Test a benadryl tablet or other legal substance that gives a known colour change to verify the situation.
