Which of the following substance is not applied on the head of a matchstick made up of a suitable wood?

Question

Accepted Answer

The correct answer to the question is Option 4: Red phosphorus. Here's a detailed explanation supporting this choice:

1. **Explanation for Option 4 (Red phosphorus):**
   - Red phosphorus is not applied on the head of a matchstick. Instead, it is typically used on the striking surface of safety matchboxes. When a match is struck against this surface, the friction causes the red phosphorus to convert into white phosphorus, which ignites and initiates the combustion of the match head. Therefore, red phosphorus is crucial for the ignition process but is not part of the match head composition itself.

2. **Explanation for why the other options are incorrect:**

- **Option 1 (Antimony trisulphide):**
     - Antimony trisulphide is indeed applied on the head of a matchstick. It acts as a fuel in the match head composition, helping to sustain the flame once the match is ignited. Its presence is essential for the match to burn effectively.

- **Option 2 (Potassium chlorate):**
     - Potassium chlorate is another component found in the head of a matchstick. It serves as an oxidizing agent, providing the necessary oxygen to support the combustion of the match head materials. This compound is crucial for the ignition process.

- **Option 3 (Starch):**
     - Starch is used as a binder in the match head composition. It helps to hold the various components together, ensuring that the match head remains intact and functions properly when struck. Starch is a common ingredient in match heads for this purpose.

In summary, red phosphorus is not applied on the head of a matchstick but is used on the striking surface of the matchbox. The other substances listed are integral components of the match head, each serving a specific role in the ignition and burning process.