Question

The head of safety match contains:
A. Antimony trisulphide and potassium chlorate
B. Antimony chloride and potassium sulphide
C. Antimony carbonate
D. potassium sulphide

Answer 1

The head of the match contains the chemical that can be ignited just by the heat produced by the friction. Antimony trisulphide and potassium chlorate both are used for burning purposes such as crackers, fireworks, explosives. Antimony chloride does not have explosive properties; it is used as a chemical reagent. Potassium sulphide is also used in fireworks.

Complete solution: Potassium chlorate is an oxidizing agent. The reaction of white phosphorus and potassium chlorate generates the heat. By using this heat antimony trisulphide ignites, so the combustion starts and antimony trisulphide burns.
So, the match head is made up of antimony trisulphide and potassium chlorate. Normally the antimony trisulphide and potassium chlorate do not react and the simple friction cannot burn the antimony trisulphide.
The cover of the matchbox has a site that contains red phosphorus mixed with powdered glass and stuck by glue.
When the head of the match is rubbed at the cover containing red phosphorus, friction generates. Which produces enough energy required to convert the red phosphorus into white phosphorus which reacts with potassium chlorate and produces heat so the antimony trisulphide burns.
So, the head of the safety match contains antimony trisulphide and potassium chlorate.

Thus, the correct option is (A).

Note: Initially the white phosphorus was applied on the matchbox. Which on rubbing produce react with potassium chlorate and produce the heat to ignite the antimony trisulphide. But the white phosphorus is dangerous. So, now a day’s red phosphorus is used. By the heat of friction red phosphorus can be converted into white phosphorus. The burning of a substance in presence of oxygen is known as combustion