THE DRYING AGENT SUITABLE FOR DRYING AMMONIA IS

• A. Calcium Chloride
• B. Calcium Oxide ✓
• C. Phosphorus(V) Oxide
• D. Concentrated H₂SO₄

To understand why calcium oxide is the suitable drying agent for drying ammonia, we need to consider the properties of both substances. Ammonia is a colorless gas with a characteristic pungent odor, commonly used in various industrial processes and as a fertilizer. It is highly soluble in water, which makes it challenging to dry efficiently.

Calcium oxide, also known as quicklime, is a white crystalline solid with many industrial applications. One of its key properties is its strong affinity for water. When exposed to moisture, calcium oxide readily reacts with water to form calcium hydroxide through the following chemical reaction:

CaO + H2O → Ca(OH)2

This reaction is highly exothermic, releasing a significant amount of heat energy. The formation of calcium hydroxide from calcium oxide and water effectively removes water molecules from the ammonia gas stream, thereby drying it.

In the context of drying ammonia gas, using calcium oxide as a drying agent helps to remove excess moisture from the gas stream, ensuring that the ammonia is in a dry state suitable for further processing or storage.

In other words, Calcium oxide, also known as quicklime, is a highly reactive substance that has a strong affinity for water. When exposed to ammonia gas, calcium oxide readily reacts with the water content in ammonia to form calcium hydroxide and effectively dry the gas. This reaction helps remove any moisture present in the ammonia gas, making it suitable for further use in industrial processes.