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A modern safety match lights when struck because:
ASunlight focused on the head ignites the match
BSodium bicarbonate in the head ignites on impact
CThe heat of friction converts some red phosphorus on the rubbing surface to white phosphorus, which reacts with potassium chlorate in the match head
DThe match head is naturally hot enough to ignite
Answer & Solution
Correct answer: C. The heat of friction converts some red phosphorus on the rubbing surface to white phosphorus, which reacts with potassium chlorate in the match head
In modern safety matches, the head contains antimony trisulphide + potassium chlorate; the box's rubbing surface has powdered glass + red phosphorus. Striking the match produces enough heat by friction to convert some red phosphorus to white phosphorus on the head, which then reacts vigorously with the potassium chlorate to ignite the antimony trisulphide. This is why the match only lights when struck against its OWN box.
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