Question

${\mathrm{CH}}_2={\mathrm{CH}}_2+{\mathrm{H}}_2\stackrel{\mathrm{Ni}}{\to }{\mathrm{CH}}_3-{\mathrm{CH}}_3$ is an addition reaction.

Complete the following reaction: $\mathrm{CH}\equiv \mathrm{CH}+{\mathrm{H}}_2\stackrel{\mathrm{Ni}}{\to }$?

Answer 1

Part 1: Analyzing the given reaction:

• As given in the question:
• $\underset{\mathrm{Ethene}}{{\mathrm{CH}}_2={\mathrm{CH}}_2}+\underset{\mathrm{Hydrogen}}{{\mathrm{H}}_2}\stackrel{\mathrm{Ni}}{\to }\underset{\mathrm{Ethane}}{{\mathrm{CH}}_3-{\mathrm{CH}}_3}$
• The above reaction is an addition reaction that is facilitated by Nickel $\left(\mathrm{Ni}\right)$ as a catalyzer.
• In this reaction, hydrogen is added to the alkene and the $\left(\mathrm{\pi }\right)$bond is broken down in the place of the pi bond, two extra hydrogens are added.

Part 2: Identifying the product of the reaction:

• $\mathrm{CH}\equiv \mathrm{CH}+{\mathrm{H}}_2\stackrel{\mathrm{Ni}}{\to }$ ?
• When alkyne is treated with hydrogen in the presence of nickel as a catalyst, an addition reaction takes place and alkene is formed which is further hydrogenated to form alkane.
• The complete reaction is: $\underset{\mathrm{Ethyne}}{\mathrm{CH}\equiv \mathrm{CH}}+\underset{\mathrm{Hydrogen}}{{\mathrm{H}}_2}\stackrel{\mathrm{Ni}}{\to }\underset{\mathrm{Ethene}}{{\mathrm{CH}}_2={\mathrm{CH}}_2}+\underset{\mathrm{Hydrogen}}{{\mathrm{H}}_2}\stackrel{\mathrm{Ni}}{\to }\underset{\mathrm{Ethane}}{{\mathrm{CH}}_3-{\mathrm{CH}}_3}$