Which of the following substances does not contain a $-COOH$ group?

Arrange the following compounds in decreasing order of their acidic strength.

One of the functional groups present in the product of the reaction between phenol and chloroform in an alkaline medium is:

Identify compound $(Z)$ in the following reaction sequence.

The product $(A)$ in the following reaction 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).