Potassium chlorate, beautiful but dangerous

Investigators probing the cause of the fireworks disaster at the Puttingal Devi temple near Kollam recently, hinted that rival teams possibly used potassium chlorate, a banned explosive. They had also probably sourced the chemical illegally from matchstick factories.

About Potassium chlorate:

Potassium chlorate was discovered by French chemist Claude Louis Berthollet during the end of the 18th Century.

Where is it used?

It is commonly used in pyrotechnics. The principal reason for using it in pyrotechnics is for the production ofbeautiful colours. Despite its inherent risk, the reason it is sometimes used in pyrotechnics is because it is cheap and easily available.

How does it work?

Potassium chlorate has very powerful oxidising ability. When heated, it decomposes to produce oxygen. The oxygen so produced fuels the flame of the lit firework, thereby increasing the temperature of the firework even further. The extra heat generated excites the electrons in the colour-producing chemicals added in the firework mixture and thus produces beautiful colours.

Why is it banned?

The oxidising property of potassium chlorate is also its biggest disadvantage when used in fireworks. It has an inherent property to become very reactive, especially when mixed with sulphur; the potassium chlorate-sulphur mixture becomes dangerously sensitive to friction and may spontaneously ignite. Hence, potassium chlorate is banned for use in fireworks.