The major product in the following reaction is:

The order of reactivity of phenol $(I)$,nitrobenzene $(II)$,and benzene $(III)$ towards nitration is:

Arrange the following phenols in decreasing order of their $pK_{a}$ values:
$(A)$ Phenol
$(B)$ ortho-Nitrophenol
$(C)$ meta-Nitrophenol
$(D)$ para-Nitrophenol

The major product of the acetylation of salicylic acid with $Ac_2O/H^+$ followed by heating with anhydrous $AlCl_3$ is

The order of acidic strength of $X, Y$ and $Z$ is:
Phenol reacts with dilute $HNO_3$ to form $X$ ($o$-nitrophenol) and $Y$ ($p$-nitrophenol). Phenol reacts with concentrated $HNO_3$ and $H_2SO_4$ to form $Z$ ($2,4,6$-trinitrophenol or picric acid).

In the Liebermann’s nitroso reaction,the changes in the colour of phenol occur as: