Discuss the estimation of nitrogen present in an organic compound by Dumas method. Mention the principles.

Explanation

Estimation of nitrogen : There are two methods to estimate nitrogen in the given organic com pound known as i) Duma.s method and ii) Kjeldahed.s method., i) Duma.s method : In this method a known weight of organic compound is heated strongly with coarse cupric oxide. Carbon and hydrogen get oxidised to carbon dioxide and water vapour respectively. Nitrogen if present is converted to nitrogen gas. Even if some nitrogen is:converted to its oxides. They are reduced by hot copper gauze to nitrogen. The product gases are collected over a solution of potassium hydroxide, Co, is absorbed by KOH solution. Nitrogen is collected over potassium hydroxide solution and its volume is found out.
`C _(x) H _(y)N_(Z) + [ 2x + (y)/(2) ] Cu O to x CO _(2) + (y ^(2))/( 2) H _(2)O+ (z)/(2) N _(2) + [ 2x + (y)/(2) ] Cu`
Suppose that .a.g of organic compound gives `V_(1)` ml of` N_(2)` at room temperature TK. If atmosphere pressure is P and aqueous tension at TK is P, then the pressure of nitrogen gas at TK is (P-p). Let (P-p) = `P_(1).` Reduce the volume of nitrogen to standard temperature 273 K and standard pressure 760 mm.
Volume of nitrogen at STP is `v = ( P _(1) V _(1))/( T _(1)) xx ( 273)/(760)`
28 g of nitrogen at STP occupies 22400 ml
7g. of nitrogen at STP occupies vml of nitrogen.
`28 xx ( V)/(22400) g`
.a. g. of organic compound `( 28 xx v)/(22400) g ` of notrogen.
100 g organic compound has ? of notrogen `= (100)/(a) xx ( 28 xx V)/(22400 )g `