Which of the following substances will give a characteristic dark color with a solution of $FeCl_3$?

In the following reaction sequence,identify the major product $Y$:
$C_6H_5OH$ $\xrightarrow{C_6H_5COCl, \text{Base}} X$ $\xrightarrow{\text{Nitration}} Y$

Phenol on treatment with dil. $HNO_3$ gives two products $P$ and $Q$. $P$ is steam volatile but $Q$ is not. $P$ and $Q$ are,respectively:

Phenol $\xrightarrow[(ii) CO_2 / 140^{\circ}C]{(i) NaOH} A$ $\xrightarrow{H^{+} / H_2O} B$ $\xrightarrow[CH_3COOH, \Delta]{Al_2O_3} C$
In this reaction,the end product $C$ is :

Identify $X$ and $Y$ in the following reaction:
$X \xrightarrow{Y} \text{Benzoquinone}$

Which product is obtained on treating phenol with concentrated $HNO_3$?