Hydrocarbons 2 Question 26
26. Which one of the following alkenes will react fastest with $\mathrm{H}_{2}$ under catalytic hydrogenation condition?
$(2000,1 \mathrm{M})$ (a)
(b)
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Answer:
Correct Answer: 26. (d)
Solution:
- Ease of catalytic hydrogenation depends upon the size of groups present at the doubly bonded carbon. Larger the size of groups, difficult the hydrogenation. Therefore, in the given situation, disubstituted reacts at faster rate than tri and tetra substituted alkenes. Among disubstituted, the stability order is :
$$ \text { cis }<\text { geminal }<\text { trans } . $$
