Prabin Kalikote

Ammonia gasis not collected by downward displacementof water because it is highly soluble in water andgives ammonium hydroxide.
NH₃ + H₂O ----------> NH₄OH

Moist red litmus paper is brought near the mouth ofgas jar filled with ammonia to testwhether the gasis ammonia or not. Since, ammoniagas is basicinnature, it turns moist red litmus paper to blue.

We all know, ammonia is lighter than air. So, itflows upward in the free state. Therefore, the gas jar isinverted to collect the ammoniagas by downwarddisplacementof air.

We all know, a hard glass test tube is slightlyinclined during preparation of ammonia gas, otherwisethe steam produced during the reaction exerts pressure, which maycrack the test tube. So, the HGTT isslanted to prevent it from cracking.

For commercial purpose, ammonia gas is manufacturedby Harber's process. In this process, a mixture of nitrogen and hydrogen (1:3) is combined directly at500ºc temperature and 200 to600 atm. For this reactionfinely powdered iron is taken as a catalyst andmolybdenumas apromoter.
N₂ + 3H₂ -----------> 2NH₃

Any three chemical properties of ammonia gas are:
- Ammonia dissolves in water and forms analkali ie, ammonium hydroxide.
NH₃ + H₂O ------> NH₄OH
-Ammonia is a basic gas. So, it reacts with acidto give salt.
NH₃ + Hcl -------> NH₄CL
-Ammonia reacts with water and Forms nitrogengas and water.
4NH₃ + 3O₂ -------> 2N₂ + 6H₂O

Any four physical properties of ammonia gas are:
-It is colorless, tastelessgas having strong pungent odor.
-It is lighter than air.
-It is highly soluble in water.
-It is basic in nature.
-It is non-combustible gas.