Question

In the Liebermann’s nitroso reaction, sequential changes in the colour of phenol occurs as

• A. Brown or red $\to$ green $\to$ red $\to$ deep blue
• B. Red $\to$ deep blue $\to$ green
• C. Red $\to$ green $\to$ white
• D. White $\to$ red $\to$ green

Answer 1

Answer: (A)

In Liebermanns nitroso reaction, phenol is treated with sodium nitrite in presence of concentrated sulphuric acid and heated gently to obtain a blue colour. It is then diluted with water to obtain red solution. On basification, with dil. $NaOH$ solution, it turns blue.