Quantitative reaction on glycerol

Solution first turns blue and then dark blue.

Scientific name: Copper sulfate first reacts with sodium hydroxide and then the product reacts with glycerin.

YouTube

Реакция глицерина с гидроксидом меди (II)

by kemiallinenkoe

Safety

Wear eye protection goggles and gloves.

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reaction formula

CuSO4 + 2NaOH → Cu(OH)2 + Na2SO4

CH2OH-CHOH-CH2OH + Cu(OH)2 → Cu(-O-CH2-CH-O-)-CH2OH

Step-by-step instruction

  1. Prepare three bakers.
  2. Fill one third of the first beaker with sodium hydroxide solution.
  3. Fill one third of the second beaker with copper sulfate solution.
  4. Fill one third of the last beaker with glycerol.
  5. Add the solution from the first beaker to the second one.
  6. The solution turns blue.
  7. Add glycerol to the obtained solution.
  8. Stir the obtained mixture with a glass rod.
  9. The liquid turns dark blue.

Scientific background

When solutions of copper sulfate and sodium hydroxide are mixed together the chemical reaction between the components leads to the formation of copper (II) hydroxide. This substance is insoluble in water and has a blue color. The reaction of copper sulfate with glycerol in alkaline conditions is used in quantitative analysis to define the amount of glycerol. The produced substance is dark-blue copper glycerate. To define glycerol content the product should be separated from the solution. Measuring copper content allows estimating the original amount of glycerol.

Danger:
Coolness:
Difficulty:

Published on 05 August 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst