Question Detail

CHM 102 Qualitative and Quantitative Analysis in Organic Chemistry Objective Question
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Question

What indicates the presence of nitrogen in Lassaigne's extract?
Options
A Yellow precipitate with AgNO₃
B Prussian blue coloration with FeSO₄ and FeCl₃
Correct Answer
C Black precipitate with lead acetate
D Purple color with sodium nitroprusside
Correct Answer

Option B is the correct answer.

Detailed Explanation

Nitrogen in the extract forms NaCN, which reacts with Fe²⁺ to form ferrocyanide, then with Fe³⁺ to give Prussian blue [Fe₄(Fe(CN)₆)₃].

Hint

Deep blue color.

Question Info

Course: CHM 102
Topic: Qualitative and Quantitative Analysis in Organic Chemistry
Type: Objective
Difficulty: Not specified
Question 802 of 1999
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