Question

Under high pressure and in presence of nickel cyanide catalyst, acetylene on polymerization gives:
A) Benzene
B) Mesitylene
C) Cyclo- octatetraene
D) Vinyl acetylene

Answer 1

HintAcetylene is an organic compound also known as narcylyn, vinylene and ethyne. When it is in pure form it cannot be handled as it is unstable. It contains a triple bond. As in this structure two atoms share three electrons with each other. It has a mild ether odour. It is soluble in chloroform and acetone.


Complete solution:
 When acetylene is polymerized under high pressure in the presence of nickel cyanide catalyst cyclo- octatetraene is formed. The reaction is known as reppe’s synthesis. The equation for the reaction is:
4\[H=C\xrightarrow{Ni{{(CN)}_{2}}}{{C}_{8}}{{H}_{8}}\] (cyclo- octatetrane)
Reppes synthesis is used for obtaining the most important product of the industrial organic. It is also used in making certain materials for the production of rubber and plastic.
Mesitylene can be formed by the action of sulphuric acid on acetone. It can also be prepared by the action of hydrochloric acid on acetone. The temperature should be maintained between \[{{100}^{o}}-{{200}^{o}}C\]. It can also be formed by the condensation process of acetone uner the presence of catalyst alumina or silica gel.

Hence, the correct option is (C).


Note:Acetylene is used in soldering metals, in the glass industry. It is used in brazing and as an additive for preservation of food. It is used in precipitation of metals. It is used as fuel additive and in carburization of steel too .It is produced by the reacting calcium carbide with water or by partial combustion of methane in air.