Assignment

1. The blue colour confirming the presence of nitrogen in an organic compound is due to the formation of:

   1. Fe₄[Fe(CN)₆]₃
   2. Na₄[Fe(CN)₆]
   3. NaCNS
   4. Na₄[Fe(CN)₅NOS]

2. Which of the following sodium fusion extract of an organic compound gives a brilliant violet color with sodium nitroprusside solution?

   1. Urea
   2. Thiourea
   3. Benzoic acid
   4. Aniline

3. Which of the following reagents is used to distinguish halogens (Cl, Br, I) in an organic compound?

   1. NH₄OH
   2. NaOH
   3. FeCl₃
   4. H₂SO₄