Explain Carius method for the determination of Halogens quantitatively in an organic compound.

Explanation

Halogens can be estimated by Carius method .
In this method a known weight of the organic compound is heated with fuming nitric acid in presence of `AgNO_(3)` in a hard glass tube . Carbon and hydrogen are oxidised to `CO_(2)` & `H_(2)O` . Halogens are converted into sivler halides . The silver halide is filtered off , washed , dried and weighted

Calculation : Mass of the organic compound = a g
Mass of silver halide formed (Ag X) = b g
`therefore` Mass of halogen in b g of Ag X ............ ?
`= ("(Atomic mass of X" xx " b) g")/( "Molecular mass of AgX") = 'C' g . `
a g of organic compound has C g of halogen
`therefore` 100 g of organic compound has ................ ?
`= (100 xx C)/( a) = (100 xx b xx "Atomic mass of X")/(a xx "Molecular mass of AgX")` (Molecular Masses : AgCl = 143.5 (108 + 35.5) , AgBr = 188 (108 + 80) , Agl = 235 (108 + 127) )