Question

If a molecule Y contains two carbon- carbon double bonds, then how many molecule of ${\text{H}}_2$ are required for the complete hydrogenation of one molecule of Y?

• A. 2
• B. 1
• C. 3
• D. 4

Answer 1

The correct option is A 2

One molecule of hydrogen gas in presence of Ni or Pd as catalyst is required for complete hydrogenation of one molecule of an unsaturated alkene with only one carbon-carbon double bond.

Since Y molecule contains two carbon-carbon double bonds, two molecule of hydrogen gas will be required for complete hydrogenation of one molecule of Y.