For the estimation of nitrogen, 1 . 4 g of an organic compound was digested by the Kjeldahl method and the evolved ammonia was absorbed in 60 ml of M 1 0 sulphuric acid. The unreacted acid required 20 ml of M 1 0 sodium hydroxide for complete neutralization. The percentage of nitrogen in the compound is

Step-by-step solution

In Kjeldahl method, Per   cent   N   =   1 . 4   N   V W Where, NV   = gram equivalent of ammonia W   = weight of the organic compound ⇒ 2 NH 3 + H 2 SO 4 excess → ( NH 4 ) 2 SO 4 Total of H 2 SO 4 used = 6 0 × 1 1 0 = 6 mm = 6 x 2 =12 gm equivalent ⇒ 2 NaOH + H 2 SO 4 → Na 2 SO 4 + 2 H 2 O NaOH for back titration = 2 0 × 1 1 0 = 2 gm equivalent gm equivalent of remaining H 2 SO 4 = 12 - 2 = 10 H 2