The reaction of concentrated $HNO_3$ with phenol forms:

How many $\sigma$ (sigma) and $\pi$ (pi) bonds are present respectively in the final product obtained by the Reimer-Tiemann reaction of phenol?

Phenol $(C_6H_6O)$ $\xrightarrow{Br_2 \text{ in } CS_2}$ $X$ (Major product)
Phenol $(C_6H_6O)$ $\xrightarrow{Br_2 \text{ in } H_2O}$ $Y$ (Major product)
What are $X$ and $Y$ in the above reaction respectively?

Phenol is more acidic than:

Explain the classification of phenols with examples.

Which of the following is $\underline{\text{NOT}}$ a dihydric phenol?