JEE Main · 2018 · 08 Apr 2018 · Offline · Practical and Analytical Chemistry

Which of the following compounds will be suitable for Kjeldahl's method for nitrogen estimation ?

(A)(see structure)
(B)(see structure)
(C)(see structure)
✓ Correct
(D)(see structure)

Answer: (C)

Solution

Kjeldahl's method works only when the nitrogen can be digested cleanly to ammonium sulfate, which rules out nitrogen held in a ring, in a nitro group, in an azo linkage or in a diazonium salt. Of the structures offered, the diazonium salt, the ring nitrogen of pyridine and the nitro group of nitrobenzene all fail on this count, while aniline,

C X_{6} H X_{5} NH X_{2}

, carries its nitrogen in a simple amino group that converts readily to

NH X_{4} X^{+}

, so aniline is the suitable compound.

JEE Main · 2018 · 08 Apr 2018 · Offline · Single correct option

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