Question

Given below are two statements :
Statement (I) : Kjeldahl method is applicable to estimate nitrogen in pyridine.
Statement (II) : The nitrogen present in pyridine can easily be converted into ammonium sulphate in Kjeldahl method.
In the light of the above statements, choose the correct answer from the options given below.

• A. Both Statement I and Statement II is false
• B. Statement I is false but Statement II is true
• C. Both Statement I and Statement II is true
• D. Statement I is true but Statement II is false

Answer 1

The Correct Option is A

The query concerns the applicability of the Kjeldahl method for quantifying nitrogen in pyridine and the ease of converting pyridine's nitrogen to ammonium sulfate via this procedure.

1. Kjeldahl Method: This method is standard for measuring nitrogen content in chemical substances, particularly organic compounds containing nitrogen as ammonia or amines. It involves digestion, neutralization, and titration steps to convert nitrogen into ammonium sulfate for measurement.
2. Pyridine: Pyridine, a heterocyclic aromatic organic compound with the formula \(C_5H_5N\), contains nitrogen within a pyridine ring. This structural arrangement prevents straightforward conversion to ammonia under typical Kjeldahl method conditions.
3. Statement Evaluation:
   • Statement I: "Kjeldahl method is applicable to estimate nitrogen in pyridine."

This statement is incorrect. The nitrogen in pyridine is part of a stable aromatic ring and does not readily convert to ammonia during the Kjeldahl digestion process. Consequently, the Kjeldahl method is unsuitable for determining nitrogen in pyridine.

• Statement II: "The nitrogen present in pyridine can easily be converted into ammonium sulphate in Kjeldahl method."

This statement is also incorrect. As previously noted, the stable aromatic nature of pyridine's nitrogen inhibits its easy conversion to ammonium sulfate.

Conclusion: Both Statement I and Statement II are false. The correct conclusion is: Both Statement I and Statement II are false.