Question

Conversions:
a) Methane to ethane
b) But-2-ene to ethanal
c) Sodium benzoate to chlorobenzene
d) Benzene to m-dinitrobenzene
e) Ethyne to benzene sulphonic acid

Answer 1

Hint: The answer to these conversion reactions involves basic reactions like chlorination, oxidation, reduction and also basic named reactions in the presence of certain catalyst and reaction conditions.

Complete step by step answer:
We have come across various types of reactions to obtain one compound from another in our chapters of organic chemistry.
Now, let us see some of the basic reactions which are involved in the conversions of these simple molecules.
a) Conversion of methane to ethane is not possible directly. Here one extra carbon atom is added. Therefore, to convert to ethane firstly methane is treated with chlorine gas in the presence of ultraviolet light to give chloromethane
- This product on further reaction with sodium metal and dry ether (solvent which does not react with sodium) gives ethane.
The reaction is,
\[\begin{align}
 & C{{H}_{4}}+C{{l}_{2}}\xrightarrow{UVlight}C{{H}_{3}}Cl+HCl \\
 & 2C{{H}_{3}}Cl+2Na\xrightarrow[ether]{dry}C{{H}_{3}}C{{H}_{3}}(or{{C}_{2}}{{H}_{6}}) \\
\end{align}\]
The last step is a reaction called Wurtz synthesis.
b) To convert but-2-ene to ethanal directly by the process called ozonolysis at around 196K where ozonolysis is carried out for the multiple bonded hydrocarbons to yield aldehyde.

c) Sodium benzoate is first converted to benzene and then on chlorination of benzene in presence of $AlC{{l}_{3}}$it gives chlorobenzene.

d) Benzene on nitration at 333K given nitrobenzene which on further nitration (fuming) yields m-dinitrobenzene.

e) Ethyne is subjected to polymerization which yields benzene and benzene is converted to benzene sulphonic acid by sulphonation reaction.

Note: The important point to be noted while solving the conversion problems is to concentrate on the question where small change can give wrong answers. In the above question b) if “ethanol” is read as “ethanol”, then the answer goes wrong.