Production of Ammonia Gas

Ammonia gas is produced in the laboratory by heating a mixture of ammonium chloride and calcium hydroxide. The gas, being lighter than air and highly soluble in water, is collected by downward displacement of air.

1. Prepare a mixture of ammonium chloride and dry-slaked lime (calcium hydroxide) in a 3:1 ratio in a round-bottom flask. Some methods suggest adding a small amount of water.
2. Clamp the flask in a slightly inclined position as shown in the apparatus diagram.
3. Connect the flask to a delivery tube that leads to a gas-collecting jar.
4. Heat the flask gently to initiate the reaction.
5. Allow the ammonia gas produced to pass into the jar, where it is collected by downward displacement of air.

📄 Ammonia Fountain (procedure for production of ammonia described) - Dynamic Science: Ammonia fountain

Laboratory Method of Preparation of Ammonia Gas (shows drying with diagram) - Kiran Sharma:

• The gas can be passed through a drying tube containing quicklime (CaO) to obtain dry ammonia.

• Eye protection and lab coat required.
• Perform in a fume cupboard to avoid inhaling ammonia gas.
• Handle hot glassware carefully to avoid burns.
• Do not overheat the mixture, as sudden gas release may cause spattering.
• Ensure apparatus is clamped securely to prevent accidents.

• Why is ammonia gas collected by downward displacement of air instead of over water? (It dissolves in water.)
• What properties of ammonia allow it to rise and displace air in the jar?
• How does an ionic reaction equation simplify the understanding of the process?
• Why is it important to use a drying agent if pure, dry ammonia is required?