1. The Preparation and Collection Of Non-Metals.
Ashvini Jagassar- 5C
Chemistry.
Mr. Dookoo

2. Section B- Descriptive Chemistry B.2. Inorganic Chemistry
Preparation and Collection of Non-Metals:
3.1 describe the industrial preparation of chlorine, sulphuric acid and ammonia;

3. The Preparation and Collection Of Chlorine.
The main method for the manufacture of chlorine is The Flowing Mercury Cathode Cell. Sodium hydroxide and hydrogen are co products . This is the electrolysis of brine (aqueous sodium chloride) using a continuously flowing mercury cathode and a graphite or titanium anode. The raw material used is concentrated sodium chloride solution (NaCl). The power requirement is approximately 4.5 V, 300,000 A, and the process is carried out at a pH of about 4.5.

4. The Flowing Mercury Cathode Cell.

5. Reactions involved in the Electrolysis of Chlorine.
Cl is discharged at the anode because it is of higher concentration than OH-
2Cl-(aq) - 2e Cl2(g)
Chlorine gas produced is collected.
At the cathode Na+ is discharged because of the mercury cathode. The normal order of discharge is reversed on a fresh metal surface (mercury).
Na+ + e Na(s)

6. The Preparation and Collection of Sulphuric Acid.
Sulphuric acid is widely manufactured using the Contact Process. This process can be divided into three stages:
The production of sulphur dioxide.
Mainly by burning sulphur in air
S(s) O2(g) SO2(g)

7. Oxidation of sulphur dioxide to sulphur trioxide.
Pure dry sulphur dioxide and oxygen are heated to 450oC and passed over a vanadium (V) oxide in silica gel catalyst.
2SO2(g) O2(g) SO3(g)
Hydration of sulphur trioxide.
Sulphur trioxide is hydrated indirectly by initially dissolving in concentrated sulphuric acid. Oleum is formed which is diluted to give concentrated sulphuric acid.
H2SO4(aq) SO3(g) H2S2O7(aq)
Oleum
H2S2O7(aq)_ + H2O(l) H2SO4(aq)

8. The Contact Process

9. The Preparation and Collection of Ammonia.
Ammonia is commercially manufactured by the Haber Process. In this process a purified nitrogen/hydrogen mixture is compressed to atm and passed over a finely divided iron catalyst. The heat evolved during the reaction maintains the optimum reaction temperature, oC.

10. N2(g) H2(g) NH3(g)
The gases leaving the reaction chamber contain 10-20% ammonia, which is removed by condensation under refrigeration or absorption by water. Uncombined nitrogen and hydrogen are recycled.
atm oC
Iron catalyst

11. Preparation of Ammonia Gas.