During the execution of Kjeldahl's method for nitrogen estimation, which of the following chemical r — Qualitative and Quantitative Analysis Chemistry Question

💡 Solution & Explanation

Kjeldahl's method involves digesting the sample with concentrated $H_2SO_4$ to form $(NH_4)_2SO_4$. The mixture is then heated with alkali to liberate $NH_3$, which is absorbed in a standard acid. The excess acid is back-titrated with standard $NaOH$. Cupric oxide ($CuO$) is used in the Dumas method and Carbon/Hydrogen estimation, not in Kjeldahl's method.