Both glycerin, and ethanol – colourless transparent liquids, belong to the class of alcohols, only glycerin – polybasic (IT incorporates three - groups), and ethanol – monobasic (respectively, IT supports only one - group). How it is possible to distinguish one substance from another?
It is required to you
- - test tubes;
- - glycerin liquid;
- - ethanol liquid;
- - laboratory scales;
- - sodium hydroxide;
- - copper vitriol;
- - glass funnel with the paper filter.
Instruction
1. Of course, to distinguish glycerin from ethanol, you can use method, widespread among chemists, – on a smell. But it is better not to resort to it as vapors of many chemicals are poisonous. Especially you should not taste liquids. This method of comparison has to be under a ban!
2. Ethyl alcohol – fluid liquid, it less dense, than water. Glycerin – viscous liquid, is more dense than water. Take two measured tanks of identical weight (test tubes or small laboratory glasses with divisions), pour in them identical amount of liquids – for example, on 5 milliliters. Carefully incline tanks, then put vertically again. Alcohol will flow down on capacity walls instantly, glycerin will flow down slowly, "viscously", leaving a film on walls.
3. Serially weigh these tanks on sensitive scales (better – laboratory). That which weighs more contains glycerin.
4. Also you can use and in a different way. For this purpose begin to flow sodium hydroxide solution to copper salt solution. Almost at once the blue deposit of hydroxide of copper – Cu(OH)2 will drop out. Transfer a little this deposit (better – after its office on the paper filter) in the transparent container with the studied substance, vigorously stir. If there glycerin really contained, hydroxide of copper will be dissolved, and solution will accept a beautiful saturated blue shade. If capacity contained ethyl alcohol, such result will not be!
5. This high-quality reaction is based on ability of polyatomic alcohols to form the painted copper glitserata. In the same way, for example, it is possible to distinguish ethylene glycol from ethyl alcohol.