Which of the following on reactions with nitrous acid, followed by treatment with NaOH produces a blue coluration?

Step-by-step solution

R - C | H 2 N O 2 + O = N - O H → R - C | = N N O 2 - O H + H 2 O Nitrolic acid Dissolve in NaOH to give blood red colouration R - C | | R - R N O 2 + H N O 2 → No reaction R − C | | R − H NO 2 + HO − N = O → R − C | | R − N NO 2 = O + H 2 O Pseudo nitrole Does not dissolve in NaOH, but gives blue colouration P h N O 2 + H N O 2 → No reaction