Why does a match burn? Why does it ignite only on the friction surface of the matchbox?

 

• Friction on the ignition surface:

P₄ + 5 O₂ –→ P₄O₁₀

If the match is struck against the striking surface, the friction causes the match to heat up. A small amount of the red phosphorus on the friction surface is converted into white phosphorus. The heat ignites the phosphorus that has reached the match head of the match when rubbing.

 

• Redoxreaction (example):

3/4 S₈ + 4 KClO₃ –→ 6 SO₂ + 4 KCl

This triggers the reaction between sulfur or antimony sulfide and oxygen. The oxygen is supplied by the oxidizing agent potassium chlorate.

The match head mass is foamed with air to optimize the burning behavior of the match head. Silicates are added to the match head, which on the one hand, dampen the reaction somewhat and thus prolong the burning time, and on the other hand, form a slag that prevents the ash from being separated from the match.

 

• Combustion of the wood (cellulose):

(C₆H₁₂O₆)_m + 6m O₂ –→ 6m CO₂ + 6m H₂O

In addition to the match head, a match consists of the actual wood impregnated with ammonium dihydrogen phosphate and dipped in paraffin. In the third phase, the fire spreads to the paraffine and then to the wood. In the process, the wood chars and forms charcoal. It would continue to glow after the flame has gone out. The impregnation with ammonium dihydrogen phosphate prevents this afterglow so that after the flame is extinguished, the match is completely extinguished.

 

Reference

• Match Head Reaction, University of Washington Department of Chemistry (accessed August 31, 2020)