X860: Prep Notes

Introduction

Addition of a liquid to a crystalline substance produces smoke an intense violet flames.

Equations:

14KMnO4(s) + 4HOCH2CH(OH)CH2OH(l)  → 7K2CO3(s) + 7Mn2O3(s) + 5CO2(g) + 16H2O(l)

Prior to Lecture  (prep time ~ 5 min.)

Assemble the following:

  1. Heat resistant mat
  2. dropper bottle of glycerol (glycerin)
  3. scoopula to arrange the powder once it is in place on the bench  
  4. goggles
  5. gloves

Prepare

Prepare a few grams of powdered KMnO4 (potassium permanganate) by grinding fresh granular KMnO4 to a fine powder with a mortar and pestle. 

Heap the powder in the center of a clear evaporating dish.

Make a depression in the center of the heap, creating a “volcano” shape, so the glycerol will remain in the depression and thus in contact with the permanganate.

To Conduct Demonstration:

  1. Set up a heat resistant mat next to an operating vent in the bench top.
  2. Add 10 to 15 drops of glycerol to the depression in the center of a pile of finely ground potassium permanganate in an evaporating dish on a heat proof surface. 
  3. Stand back!  Within a few seconds, the glycerol will be violently oxidized by the permanganate producing smoke and violet flames.

Demo Time: ~10 minutes

Safety and Disposal

This is a delayed reaction and produces intense heat, flames, and smoke.  Perform only in a well-ventilated room and on a heat-proof surface.  Wear goggles.