Manufacturing Of Products Flashcards Preview

Chemistry > Manufacturing Of Products > Flashcards

Flashcards in Manufacturing Of Products Deck (11):

Manufacturing of sodium hydroxide

Manufactured by the electrolysis of a concentrated solution of sodium chloride. Hydrogen is a by product

+anode: chlorine loses electrons, chlorine molecules formed

-cathode: water molecules gain electrons, hydroxide ions and hydrogen molecules formed



Necessary to keep apart sodium hydroxide and chlorine so they don't make bleach


Uses of sodium hydroxide

Manufacture of
Bleach, paper, soap, detergents


Uses of chlorine

Sterilising water supplies
Manufacture of:
Bleach, hydrochloride acid, PVC


Stages of sulphuric acid manufacture

Sulfur dioxide -> burning sulfur in air
Sulfur trioxide -> sulfur dioxide reacted with oxygen
Oleum -> sulfur trioxide absorbed into concentrated sulfuric acid
Sulfuric acid -> Oleum carefully diluted


Manufacturing sulfuric acid exras

Vanadium oxide catalyst
Reversible reaction
Position of equilibrium
Forward action is exothermic
Yield of sulfur trioxide high at low temperatures but very slow
450*C compromise
Yield is high at low pressures so not economical to go higher


Manufacture of sulfuric acid

Air + sulfur dioxide -> mixture of gases is cleaned by electrostatic precipitation (400-500*C) (2 atmospheres)

Mixture of gases passed over vanadium oxide catalyst
Oxygen combined with carbon dioxide to form sulfur trioxide
-98% yield

->unreacted gases recycled
---->sulfur trioxide dissolved in concentrated sulfuric acid -> oleum

Oleum acts with water forming sulfuric acid


Sulfuric acid uses

Manufacture of detergents
Manufacture of fertilisers
Manufacture of paints


Manufacture of ammonia

Nitrogen(air) + hydrogen (natural gas, cracking)

Reaction is reversible, can reach an equilibrium (shift to right, high yield of ammonia)

Low temperature, high pressure (compromise of 450*C or to slow)

Very high pressures (200 atmospheres) -> expensive
(energy required, container, thick walled pipes)


Manufacture of ammonia general

Catalyst used : many metals will work
Most economical is iron

Only 15% of hydrogen and nitrogen converted to ammonia


Uses of ammonia

Manufacture of:
Fertilisers, nitric acid, nylon