Sulphur acid, considered to be the King of chemicals, is mainly manufacture by the

Options

A. Lead chamber process
B. Contact process
C. Ostwald process
D. Bikelend -Eyde process

Answer

2

Explanation

In acient days,`H_(2)SO_(4)` was called oil of vitriol as it was prepared by distilling ferrous sulphate (Green vitriol )
`2FeSO_(4).7H_(2)O overset(Delta)rarr Fe_(2)O_(3)+underset("(Oil of virtol)")(H_(2)SO_(4))+SO_(2)+13H_(2)O`
By far the most important commercial process for its manufacture is the contact process in which `SO_(2)` is oxidized by air to `SO_(3)` using a catalytic surface. Formely a Pt gauze or platinized asbestos was used as catalyst. This has now been replaced by`V_(2)O_(5)`,which is slightly less efficient but is cheaper and less easily poisoned.
The `SO_(3)` could be mixed with water to yield `H_(2)SO_(4)`, but the reaction is violent and produces a dense chemical mist which is difficult to condense .Instead the `SO_(3)`, is passed into `98% H_(2)SO_(4)`, forming pyrosulphuric acid.sometimes called oleum of fuming sulphuric acid .This solution may be sold as oleum, or diluted with water to give concentrated sulphuric acid which is `98%` mixture with water (an`18M`solution)
`2SO_(2)(g)+O_(2)(g) hArr 2SO_(3)(g)`
`SO_(3)(g)+H_(2)SO_(4)(l)rarrH_(2)S_(2)O_(7)(l)`
`H_(2)S_(2)O_(7)(l)+H_(2)O(l)rarr2H_(2)SO_(4)(l)`
The older lead chamber process is now obsolete. Essentially this consists of oxidizing a mixture of sulphur dioxide and water to sulphuric acid using nitrogen dioxide as an oxygen carrier.The reaction can be experesses in simplest terms by the equation:
`H_(2)O+SO_(2)+NO_(2)rarrH_(2)SO_(4)+NO`
Here `NO_(2)` also acts as a homogenous catalyst .The nitric oxide then combines with oxygen to form more nitrogen dioxide which is used again.
`2NO+O_(2)rarr2NO_(2)`
The disadvanges of the lead chamber process were that it only produced `78% H_(2)SO_(4)` not concentrated `H_(2)SO_(4)` and the acid was less pure than that from the Contact process. Lead chamber acid (being less pure) is very suitable for making fertilizers while contact acid (being more pure)is preferred for uses such as food processing and drug manufacture.