question_answer

Phenol \[\xrightarrow{NaN{{O}_{2}}|{{H}_{2}}S{{O}_{4}}}B\xrightarrow{{{H}_{2}}O}C\xrightarrow{NaOH}D\] name of the reaction is:

A)  Liebermanns reaction

B)  Phthalein fusion test

C)  Reimer Tiemann reaction

D)  Schotten-Baumann reaction

Correct Answer: A

Solution :

\[Phenol\xrightarrow{NaN{{O}_{2}}/{{H}_{2}}S{{o}_{4}}}B\xrightarrow{{{H}_{2}}O}\] \[C\xrightarrow{NaOH}D\] This is Liebermanns nitroso reaction of phenol. When phenol is warmed with sodium nitrite and 1 cc. cone. \[{{H}_{2}}S{{O}_{4}}\], blue colour is obtained which on adding water, becomes red. This again turns to blue on adding \[NaOH\]. Deep blue colour is due to the formation of sodium salt of indophenol.