Accurate said sample is about 1.5 g, soluble in 40 ml new boiling and cooling water, cold to 15 ℃, with phenolphthalein test solution (TS - 167) several drops, with 1 mol/L acid titration.
When the pink disappears, record the amount of acid consumed, and the methyl orange test fluid (ts-148), which continues titrating to the continuous, unfading pink.
Recording the total volume of acid required for titration.
Each Ml of 1 molar of sulphuric acid is the equivalent of 56.1 mg per milliliter.