Question

The catalytic hydrogenation is more easier in case of which alkene?

• A. $(a{)}_{\underset{H}{╱}}^{\stackrel{R}{╲}}C=C{H}_2$
• B. $(b{)}_{\underset{H}{╱}}^{\stackrel{R}{╲}}C=C_{\stackrel{╲}{H}}^{\underset{╱}{R}}$
  
• C. $(c{)}_{\underset{R}{╱}}^{\stackrel{R}{╲}}C=C_{\stackrel{╲}{H}}^{\underset{╱}{R}}$
• D. $(d{)}_{\underset{R}{╱}}^{\stackrel{R}{╲}}C=C_{\stackrel{╲}{R}}^{\underset{╱}{R}}$

Answer 1

The correct option is B $(b{)}_{\underset{H}{╱}}^{\stackrel{R}{╲}}C=C_{\stackrel{╲}{H}}^{\underset{╱}{R}}$


More substituted alkenes are more stable, due to the +I effect of alkyl groups, which strengthens the C=C pi bond. This means that it'll be harder to break down substituted alkenes.
Hence, hydrogenation will be easier in the case of less substituted alkenes.