Question

write the help of le chateliar principle explain the synthesis of selpheri acid with the help of contact process?​

Answer 1

Answer:

The Contact Process is used in the manufacture of sulfuric acid. This Modules explain the reasons for the conditions used in the process by considering the effect of proportions, temperature, pressure and catalyst on the composition of the equilibrium mixture, the rate of the reaction and the economics of the process. The Contact Process:

Step 1: Make sulfur dioxide

Step 2: Convert sulfur dioxide into sulfur trioxide (the reversible reaction at the heart of the process)

Step 3: Convert sulfur trioxide into concentrated sulfuric acid

Step 1: Making sulfur dioxide

This can either be made by burning sulfur in an excess of air:

S(s)+O2(g)→SO2(g)(1)

or by heating sulfide ores like pyrite in an excess of air:

4FeS2(s)+11O2(g)→2Fe2O3(s)+8SO2(g)(2)

In either case, an excess of air is used so that the sulfur dioxide produced is already mixed with oxygen for the next stage.

Step 2: Converting sulfur dioxide into sulfur trioxide

This is a reversible reaction and exothermic.

2SO2(g)+O2(g)⇌2SO3(g)ΔH=−196kJ/mol(3)

A flow scheme for this part of the process looks like this:

The reasons for all these conditions will be explored in detail further down the page.

Step 3: Converting sulfur trioxide into sulfuric acid

This cannot be done by simply adding water to the sulfur trioxide; the reaction is so uncontrollable that it creates a fog of sulfuric acid. Instead, the sulfur trioxide is first dissolved in concentrated sulfuric acid:

H2SO4(l)+SO3(g)→H2S2O7(l)(4)

The product is known as fuming sulfuric acid or oleum, which can then be reacted safely with water to produce concentrated sulfuric acid - twice as much originally used to make the fuming sulfuric acid.

H2S2O7(l)+H2O(l)→2H2SO4(