The catalyst used in Haber's process is:

1. Molybdenum
2. Platinum
3. Nickel
4. Iron

Nitrogen gas can be obtained by heating

1. Ammonium nitrate
2. Ammonium nitrite
3. Magnesium nitride
4. Ammonium chloride

The gas collected by downward displacement of air is

1. HCl
2. NH₃
3. CO₂
4. H₂S

In the Haber's process, the ratio of reactants nitrogen and hydrogen is:

1. 2 : 3
2. 3 : 2
3. 1 : 3
4. 3 : 1