Ans 1:
Ammonia is not collected over water since it is highly soluble in water
Ans 2:
Ammonia gas is lighter than air and hence collected by the downward displacement of air.
Ans 3:
The carbon dioxide is very cold as it comes out of the extinguisher, so it cools the fuel as well.
Ans 4:
H₂SO₄ is not used in the preparation of carbon dioxide Because the calcium sulphate formed is insoluble in water. So, CO₂ will not form.
Ans 5:
The opening of hard glass test tube is slanted down during laboratory preparation of ammonia gas because Ammonia gas is not collected in the gas jar by upward displacement of air because it is lighter than air
Ans 6:
Magnesium is reactive enough to be combusted and oxidized in a reaction with carbon dioxide:
The magnesium strip burns brightly in the air, but continues to burn in the carbon dioxide environment
-TheUnkownScientist