Reagents

preparation

3% solution of aluminium chloride

3 g of aluminum chloride AlCl₃·6H₂O was placed in a volumetric flask of 100 ml, 70 ml of alcohol 70% (v/v) was added to dissolve, and adjusted volume solution of the same solvent was added to the mark and mixed. The freshly prepared solution was used.

10%, 40% sodium hydroxide

10 g (40 g) of sodium hydroxide NaOH was placed in a volumetric flask of 100 ml, 70 ml of distilled water R added, dissolved and adjusted volume of the solution of the same solvent was added to the mark and mixed.

1% solution of picric acid

1 g picric acid was placed in a volumetric flask of 100 ml, 70 ml of distilled water R was added, dissolved and adjusted to the same volume of the solution to the mark with solvent, stirred. The freshly prepared solution was used.

20% solution of sodium carbonate

20 g of sodium carbonate Na₂CO₃ was placed in a volumetric flask of 100 ml, 70 ml of distilled water R was added, dissolved and adjusted to the same volume of the solution to the mark with solvent and stirred. The freshly prepared solution was used.