Manufacturing Sulphuric Acid Reactions Chemistry FuseSchool

sulfuric acid is very valuable chemical it is used in the manufacture of detergents dyes fabrics fertilizers paints and plastics and in many other products but how is sulfuric acid made sulfuric acid is made in free stage process called the contact process in stage 1 sulfur is obtained in its elemental form solid it is melted and is then combusted in oxygen what do you think is formed at this stage could you write chemical equation for this pause think and continue when you're ready the product formed at this stage is sulfur dioxide and the chemical equation for this is shown did you get it right in stage 2 the sulfur dioxide is converted into sulfur trioxide the reaction is in equilibrium which means that as the product is formed the reverse reaction can also occur and it can break down into its reactants what can be done to this process to speed it up and to force the equilibrium into forming more sulfur trioxide pause the video and continue in ready this reaction can be sped up to form sulfur trioxide by adding catalyst vanadium oxide this is an exothermic reaction which means it gives out Heat usually this means that the formation of sulfur dioxide the backward reaction would be favored at higher temperatures however the catalyst needs temperature over 400 degrees centigrade for it to work so the idea is trade off the reaction actually takes place at 450 degrees centigrade you need the gasses to reach equilibrium within the very short time that they are in contact with the catalyst in the reactor so having an increased temperature ensures high rate of reaction meaning you established forward reaction quickly finally in stage free sulphur trioxide is converted into very concentrated sulfuric acid and the equation is shown now this liquid is also known as Oleum is very viscous and releases acidic fumes it is very important at this stage to add water carefully usually as mist to sulfur trioxide this is because the reaction is very exothermic so mixing it with pure water would release mist of sulfuric acid that would escape into the air 99.5% pure sulfuric acid is then collected and is shipped off to where it is needed next there are some acidic waste gases from stage free which can escape and cause local acid rain here's challenge for you what can you fit the chimney with to stop these gases from being released into the atmosphere the correct answer is that the chimney is usually fitted with acidic scrubbers these are bases like sodium carbonate on contact they neutralize the fumes forming salt and water other ways to minimize the release of any sulfur oxides is by recycling gases between stages 2 & 3 in summary the contact process converts sulfur to sulfur dioxide by combusting sulfur in air the sulfur dioxide produced is heated to 450 degrees centigrade over vanadium oxide catalyst this produces sulfur trioxide the sulfur trioxide is treated with fine mist of water and 99.5% sulfuric acid is collected the acidic fumes produced are treated with acidic scrubbers to prevent local acid rain you