Question

Acetophenone cannot be prepared easily starting from
A.${{C}_{6}}{{H}_{5}}C{{H}_{3}}$
B.${{C}_{6}}{{H}_{6}}$
C.${{C}_{6}}{{H}_{5}}CH(OH)C{{H}_{3}}$
D.${{C}_{6}}{{H}_{5}}C\equiv CH$

Answer 1

We need to see each option whether they are able to convert into Acetophenone or not as there are many ways and reactions to convert benzene, alcohol and acetylene to aldehyde easily. Acetophenone is the formula's chemical compound ${{C}_{6}}{{H}_{5}}COC{{H}_{3}}$. It's the shortest ketone of aromatics. This viscous, colourless liquid is a precursor to valuable resins and fragrances.

Complete answer:
Let’s consider our first option which is Toluene ${{C}_{6}}{{H}_{5}}C{{H}_{3}}$ ,with toluene we cannot prepare Acetophenone easily as it has $-C{{H}_{3}}$ group which cannot be converted easily into$-COC{{H}_{3}}$ group. Hence we can say that Acetophenone cannot be prepared easily starting from ${{C}_{6}}{{H}_{5}}C{{H}_{3}}$.
Now let’s go to our second option which is Benzene${{C}_{6}}{{H}_{6}}$ ,as we can change Benzene into toluene by the help of Friedel Crafts acylation of benzene with acetyl chloride in presence of anhydrous aluminium chloride will give us acetophenone. So here Benzene is able to convert into Acetophenone easily.
${{C}_{6}}{{H}_{6}}+C{{H}_{3}}-COCl\xrightarrow[-HCl]{AlC{{l}_{3}}}{{C}_{6}}{{H}_{6}}-CO-C{{H}_{3}}$
Now let’s go to our third option which is $1-phenyle\text{ }ethanol$ ${{C}_{6}}{{H}_{5}}CH(OH)C{{H}_{3}}$ , here we can convert ${{C}_{6}}{{H}_{5}}CH(OH)C{{H}_{3}}$into Acetophenone with easily by different reactions. So, here also$1-phenyle\text{ }ethanol$ is able to convert into Acetophenone easily.
Now let’s proceed to our last option Phenyl acetylene${{C}_{6}}{{H}_{5}}C\equiv CH$ , when we treat${{C}_{6}}{{H}_{5}}C\equiv CH$with $HgS{{O}_{4}}/{{H}_{2}}S{{O}_{4}}.{{H}_{2}}O$ will give Acetophenone as a product. So here Phenyl acetylene is also able to be converted into Acetophenone easily.
${{C}_{6}}{{H}_{5}}C\equiv CH\xrightarrow[{{H}_{2}}S{{O}_{4}}.{{H}_{2}}O]{HgS{{O}_{4}}}{{C}_{6}}{{H}_{5}}C(O)C{{H}_{3}}$.
So let us conclude that only Toluene ${{C}_{6}}{{H}_{5}}C{{H}_{3}}$ is only option here which cannot to prepared easily if we start with it.

Note:
We can convert methyl group into carboxylic group by oxidation and a haloform reaction with halogens like iodine, bromine, or chlorine can convert it into haloform and we can convert methyl ketones into corresponding carboxylic acid and haloforms too but it is not easy to convert methyl group into $-COC{{H}_{3}}$.