What will be the product $(A)$ in the following reaction?
$1,4-\text{dibromocyclohexa-1,4-diene} + 2Na \rightarrow (A)$

Assertion : Cyclopentadienyl anion is much more stable than allyl anion.
Reason : Cyclopentadienyl anion is aromatic in character.

In the following reaction,$X, Y$ and $Z$ are

The products $P$ and $Q$ in the following sequence of reactions are:
$p$-Methylanisole $\xrightarrow{Li, EtOH, NH_3(l)} P$ $\xrightarrow[(ii) -78^{\circ}C, Me_2S]{(i) O_3 (1 \text{ equiv.})} Q$

The product $(Z)$ of the following reaction is

What is the role of $HNO_3$ in the nitrating mixture used for the nitration of benzene?