Question

In the estimation of nitrogen by Kjeldahl's method 0.933 g of an organic compound 'X' was analyzed. Ammonia evolved was absorbed in 60 mL of 0.1 M H$_2$SO$_4$. The unreacted acid requires 20 mL of 0.1 M NaOH for complete neutralization. The compound 'X' is

• A. C$_6$H$_5$CH$_2$NH$_2$
• B. C$_6$H$_5$NH$_2$
• C. CH$_3$CH$_2$NH$_2$
• D. CH$_3-CO-NH_2$

Hint:

In Kjeldahl's method, the key calculation involves a back titration. 1. Find initial meq of acid. 2. Find meq of base used for back titration (= unreacted acid). 3. Subtract to find meq of acid that reacted with NH$_3$. This equals meq of N. 4. Convert meq of N to mass of N (Mass = meq $\times$ Eq. Wt. = meq $\times$ 14/1000). 5. Calculate the percentage and compare with options.

Answer 1

The Correct Option is B