the preparation and collection of non-metals. ashvini jagassar- 5c chemistry. mr. dookoo
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The Preparation and The Preparation and Collection Of Non-Collection Of Non-
Metals.Metals.Ashvini Jagassar- 5C
Chemistry.Mr. Dookoo
Section B- Descriptive Section B- Descriptive ChemistryChemistry
B.2. Inorganic B.2. Inorganic ChemistryChemistry
Preparation and Collection of Non-Metals:
3.1 describe the industrial preparation of chlorine,
sulphuric acid and ammonia;
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.
The Flowing Mercury Cathode Cell.
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)
The Preparation and Collection of Sulphuric Acid.
Sulphuric acid is widely manufactured using the Contact Contact ProcessProcess. 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)
• 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.vanadium (V) oxide in silica gel catalyst.
2SO2(g) + O2(g) 2SO3(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)
OleumH2S2O7(aq)_ + H2O(l) 2H2SO4(aq)
The Contact Process
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 200-350 atm and passed over a finely divided iron catalyst. The heat evolved during the reaction maintains the optimum reaction temperature, 350-400oC.
N2(g) + 3H2(g) 2NH3(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.
200-350 atm
350-400oC
Iron catalyst
Preparation of Ammonia Gas.
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