Which of the following substances are present on the rubbing surface of a matchbox ?

Correct Answer: Glass powder and red phosphorus

Explanation:

The striking surface on the side of a safety matchbox is specially designed to ignite a match safely through friction.

This rubbing surface contains a mixture of powdered glass (or sand) and red phosphorus:

1. Glass Powder: Acts as an abrasive agent to provide the necessary friction when the match head is struck against the surface.

2. Red Phosphorus: Converts into a small amount of white phosphorus due to the heat generated by friction. White phosphorus readily reacts with the potassium chlorate present in the match head to initiate combustion.

Therefore, the substances present on the rubbing surface of a matchbox are glass powder and red phosphorus.