Correct Option
The correct option is (a).
Explanation
The safety matchstick is designed to prevent accidental ignition by separating the combustible components from the ignition initiator. The chemical reaction relies on friction to trigger a sequence involving red phosphorus, an oxidizer, and a fuel.
Statement-wise Analysis
- Statement 1 is Correct: The rubbing surface (side of the matchbox) contains powdered glass to provide friction and red phosphorus. Red phosphorus is used because it is much less dangerous and reactive than white phosphorus at room temperature.
- Statement 2 is Incorrect: Upon striking the matchstick against the rubbing surface, the friction generates heat. This heat causes a small amount of red phosphorus to convert into white phosphorus. Therefore, the red phosphorus undergoes a chemical change (allotropic transformation) rather than remaining unchanged.
- Statement 3 is Incorrect: The white phosphorus formed immediately reacts with potassium chlorate ($KClO_3$) present in the matchstick head, not antimony trisulphide, to produce enough heat. This heat then ignites the antimony trisulphide (the fuel) to start the combustion. Potassium chlorate acts as the oxidizing agent (source of oxygen), while antimony trisulphide acts as the combustible material.
Key Takeaway
Safety Match Mechanism: The rubbing surface contains Red Phosphorus (initiator) and glass; the match head contains Potassium Chlorate (oxidizer) and Antimony Trisulphide (fuel). Friction converts Red P to White P, which reacts with the oxidizer to ignite the fuel.