In Kjeldahl ‘s method, the  gas evolved from  1.325 g sample of a fertilizer is passed into 50.0 mL of 0.2030 N H2SO4.    25.32mL  of 0.1980  N NaOH  are required for the titration of unused acid. The percentage of nitrogen in fertilizer  is

Meq.  of H2SO4  taken to absorb NH3=50×0.2030 Meq.  of H2SO4  left after NH3  absorption=Meq.  of  NaOH  used for H2SO4=25.32×0.1980 ∴  Meq.  of H2SO4  used for NH3=50×0.2030−(25.32×0.1980) Or (NV)  used for NH3=5.137 ∴               %N=1.4×NVwt.of substance=1.4×5.1371.325=5.43%