Consider the following reactions. Total number of electrons in the...

Step 1: The starting material is an aldohexose (like D-glucose). On prolonged heating with $HI$, it undergoes reduction to form n-hexane. This indicates that all six carbon atoms are linked in a straight chain.
$\text{CHO}-(\text{CHOH})_4-\text{CH}_2\text{OH} \xrightarrow{\text{HI, } \Delta} \text{CH}_3-\text{CH}_2-\text{CH}_2-\text{CH}_2-\text{CH}_2-\text{CH}_3$ (n-hexane)

Step 2: n-Hexane, when passed over heated $V_2O_5$ at $773 \text{ K}$ and $10-20 \text{ atm}$ pressure, undergoes aromatization (dehydrogenation and cyclization) to form benzene.
$\text{n-hexane} \xrightarrow{V_2O_5, \text{ 773 K, 10-20 atm}} \text{C}_6\text{H}_6$ (Benzene)

Step 3: Benzene reacts with benzoyl chloride ($\text{C}_6\text{H}_5\text{COCl}$) in the presence of anhydrous $\text{AlCl}_3$ to form benzophenone. This is a Friedel-Crafts acylation reaction.
$\text{C}_6\text{H}_6 + \text{C}_6\text{H}_5\text{COCl} \xrightarrow{\text{Anhyd. AlCl}_3} \text{C}_6\text{H}_5-\text{CO}-\text{C}_6\text{H}_5$ (Benzophenone)

Step 4: Analyze the product (X), which is benzophenone.
The structure of benzophenone consists of two phenyl rings attached to a carbonyl group.
- Each phenyl ring contains $3$ $\pi$ bonds, so two rings have $6$ $\pi$ bonds.
- The carbonyl group ($\text{C=O}$) contains $1$ $\pi$ bond.
- Total number of $\pi$ bonds = $6 + 1 = 7$.
- Total number of $\pi$ electrons = $7 \times 2 = 14$.
- The oxygen atom in the carbonyl group has $2$ lone pairs of electrons.
- Total number of lone pair electrons = $2 \times 2 = 4$.

Total number of electrons in the $\pi$ bonds and lone pairs = $14 + 4 = 18$.

Answer: $18$