Which among the following chemicals is used for control of humidity?

Silica gel

The correct answer is Option (2) → Silica gel

Humidity control is achieved using substances that absorb moisture from air.

Silica gel is a desiccant that adsorbs water vapour.

Silica gel is a highly porous, granular form of silicon dioxide that acts as a powerful desiccant. It has an extremely high surface area (around 800 m²/g), which allows it to effectively adsorb water molecules from the air through physical forces rather than chemical reactions. Because it is non toxic and can be regenerated by heating, it is the standard choice for controlling humidity in packaging for electronics, pharmaceuticals, and food.

Option 1: Charcoal- Charcoal can adsorb gases and impurities. However, it is not primarily used for controlling humidity.

Option 2: Silica gel - Silica gel has a porous structure. It adsorbs moisture from air effectively. Hence, widely used as a drying agent.

Option 3: Ammonia gas -Ammonia is a gas and does not absorb moisture. Not used for humidity control.

Option 4: Sodium chloride Common salt does not act as an effective desiccant.