Question:
Kjeldahl's method cannot be used to estimate nitrogen for which of the following compounds?
(1) $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NO}_{2}$
$\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}$
$\mathrm{CH}_{3} \mathrm{CH}_{2}-\mathrm{C} \equiv \mathrm{N}$
Correct Option: 1
Solution:
Kjeldahl's method for estimation of nitrogen is not applicable for nitrobenzene $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NO}_{2}$. because reaction with $\mathrm{H}_{2} \mathrm{SO}_{4}$, nitrobenzene can not give ammonia.