Hydrocarbons - Result Question 4

5. Which one of the following alkenes when treated whith HCL yields majorly an anti Markownikov product?

(2019 Main, 8April II)

(a) $\mathrm{Cl}-\mathrm{CH}=\mathrm{CH}_2$

(b) $\mathrm{H}_2 \mathrm{~N}-\mathrm{CH}=\mathrm{CH}_2$

(c) $\mathrm{CH}_3 \mathrm{O}-\mathrm{CH}=\mathrm{CH}_2$

(d) $\mathrm{F}_3 \mathrm{C}-\mathrm{CH}=\mathrm{CH}_2$

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Answer:

Correct Answer: 5 . (d)

Solution:

  1. Attachment of electron donating group $(+R$ or $+I)$ with $s p^2$-carbon of an unsymmetrical alkene supports Markownikov’s addition rule through electrophilic-addition-pathway. But, attachment of electron-withdrawing group ( $-R$ or $-I$ ) for the same will follow anti-Markownikov’s pathway (even in absence of organic peroxide which favours free radical addition) through electrophilic addition pathway. The product formed by given alkenes when treated with HCl .