You will need
- - the tubes;
- - glycerin;
- - lye (sodium hydroxide or potassium hydroxide);
- - copper sulfate (II).
Glycerin is an organic substance that belongs to the class of polyhydric alcohols, in particular trivalent. This means that it has three hydroxyl groups. The physical properties of the glycerin has viscosity and is odorless. Got its name for the sweet taste. The word "glikos" translates as sweet, because hence its name – glycerol.
To determine glycerinand enough to give a qualitative response that reliably indicate the presence of designated compounds in the flask. For this purpose, a freshly prepared solution of copper hydroxide (II) with glycerinω gives the dissolution of the precipitate, and the solution acquires a beautiful blue color.
Take the tube, pour into it 2 ml of copper sulfate solution (II), then gradually add the solution of sodium hydroxide or potassium hydroxide (alkalis). The reaction will observe the sedimentation rate of the blue colour due to the formation of copper hydroxide (II).
In another test tube pour 2 ml of glycerinand dilute 4 ml of distilled water, close the vial with a stopper and shake for better mixing. To a freshly prepared precipitate of copper hydroxide (II), cautiously add a solution of glycerinand, close the vial with a stopper and carefully shake the mixture.
The precipitate is dissolved almost immediately, and the reaction produced a solution of saturated bright blue color that occurs due to the formation of complex compounds of glycerate of copper (II). This is the simplest qualitative reaction, confirming the presence of glycerol.
When performing experience that is sure to follow the safety regulations, especially when working with alkalis. In contact with lye, wash the exposed skin surface with plenty of water and treat with a weak solution of boric or citric acid.