Animated Solution for Chemistry - Organic Chemistry: considering the above reaction, the major product among the following is

Let's break down this organic transformation. We are starting with a ketone, specifically 4-ethylhexan-2-one. Notice the carbonyl group ($>\text{C=O}$) at position two, and an ethyl branch at position four. We have a two-step reaction sequence ahead of us, and each step utilizes a very specific, classic named reaction or process.

The Clemmensen Reduction

Our first reagent is Zinc amalgam with concentrated Hydrochloric acid ($\text{Zn(Hg)/HCl}$). Does this ring a bell? Yes, this is the classic Clemmensen reduction!

Its primary job is to completely strip away the oxygen from the carbonyl group and replace it with two hydrogen atoms, converting the ketone into an alkane.

Let's see what happens after the reduction. The double-bonded oxygen is gone. Our 4-ethylhexan-2-one has now been reduced to an alkane. If we number the longest chain, we get a six-carbon hexane chain with an ethyl group at the third carbon. So, our intermediate is 3-ethylhexane.

The Aromatization Magic

Now for the second step. We are treating this alkane with Chromium oxide (${\text{Cr}}_2{\text{O}}_3$) at a high temperature of $773\text{ K}$ and high pressure ($10-20\text{ atm}$). These are the exact conditions for aromatization.

When an alkane has six or more carbons in its main chain, these reagents force it to undergo cyclization and dehydrogenation to form a stable benzene ring. Watch closely how this happens. The main chain of our intermediate has exactly six carbons. Under these harsh conditions, the two ends of this six-carbon chain will connect with each other, forming a six-membered ring.

Once the ring closes, the catalyst removes four molecules of hydrogen gas ($-4{\text{H}}_2$), creating alternating double bonds. We get a highly stable aromatic benzene ring!

But what about the ethyl branch? It was attached to the third carbon of the chain, so it simply remains attached to the newly formed benzene ring. Our final major product is Ethylbenzene.

Comparing our result with the given options, we can clearly see that option (a) perfectly matches our derived structure of Ethylbenzene. This question beautifully combined a classic reduction with an aromatization concept. Always trace your longest chain carefully in such problems!