Question

What are the required conditions for catalytic hydrogenation of alkynes?

• A. Nickel as catalyst
• B. High temperature
• C. Low temperature
• D. Vanadium pentoxide as catalyst

Answer 1

Answer: (A), (B)

High temperature

Hydrogenation reactions are addition reactions in which hygrogen atoms are added to an alkene.

For example, vapours of ethene mixed with hydrogen are passed over a heated catalyst (Ni or Pd or Pt) at high temperatures, which results in the formation of ethane.
${\mathrm{CH}}_2={\mathrm{CH}}_2\left(g\right)+H_2\left(g\right)\underset{}{\overset{\mathrm{Ni}/\mathrm{Pd}}{\to }}{\mathrm{CH}}_3-{\mathrm{CH}}_3\left(g\right)\mathrm{Ethene}\mathrm{Ethane}$