Choose the letter corresponding to the correct answer from — A : NO₂, B : NO, C : N₂, D : N₂O

The gas obtained when –

1. Dry ammonia and dry oxygen gas are ignited together.
2. Ammonia is passed over heated litharge.
3. A greenish yellow gas reacts with excess ammonia.
4. (a) Dry NH₃ and O₂ are passed over heated Pt.
   (b) The gaseous product obtained is further oxidized.
5. Ammonium nitrite undergoes thermal decomposition.

State the colour of :

1. Phenolphthalein solution after passage of ammonia through it.
2. Copper (II) hydroxide solution after addition of ammonium hydroxide in excess to it.
3. The flame obtained on burning dry ammonia in oxygen.
4. The solution obtained on addition of excess ammonium hydroxide to zinc sulphate solution.
5. The vapours obtained when ammonia-oxygen gas mixture is passed over heated Pt.

Give reasons for the following:

An aqueous solution of ammonia acts as a weak base.

Give reasons for the following:

A mixture of ammonium nitrate and slaked lime are not used in the lab. preparation of ammonia gas.