A sample of 0.50 g of an organic compound was treated according to Kjeldahl's method. The ammonia evolved was absorbed in 50 mL of 0.5 M `H_(2)SO_(4)`. The residual acid required 60 mL of 0.5 M solution of NaOH for neutralisation. What would be the percentage composition of nitrogen in the compound?

Explanation

Total milli equivalent (mEq.) of `H_2SO_4` taken
`=50xx0.5xx2`
`=50`mEq.
(Dibasic acid)
Excess `H_2SO_4=mEq. Of NaOH`
`=60xx0.5xx1=30mEq`.
(monoacidic base)
mEq. Of `H_2SO_4` used to neutralise `NH_3=(50-30)=20`
percentage of N
`=(1.4xxmEq." of "H_2SO_4" used to neutralise "NH_3)/("mass of substance")`
`=(1.4xx20)/(0.5)=56%`