Question

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

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The correct option is A

Explanation for correct option: A

1. In Kjeldahl's method, compounds containing the amine group are heated with concentrated Sulphuric acid (${\mathrm{H}}_2{\mathrm{SO}}_4$).
2. Nitrogen is converted to Ammonium sulfate and then is heated with the excess sodium hydroxide.
3. The liberated ammonia gas is then absorbed in an excess standard solution of sulphuric acid.

Explanation for incorrect answer:

(B)

1. Kjeldahl method is not applied to compounds containing nitro group.
2. Option B contains nitro group.

(C)

1. Kjeldahl method is not applied to compounds containing diazo group.
2. Option C consists of diazo group.

(D)

1. Kjeldahl method is not applied to compounds containing Nitrogen.
2. The option D contains Nitrogen in the ring.
   Hence, option A is the correct answer.