1.

(a) Give a detailed account on the different mechanisms followed in elimination reaction.

Answer» <html><body><p></p>Solution :(a) Elimination reactions <a href="https://interviewquestions.tuteehub.com/tag/may-557248" style="font-weight:bold;" target="_blank" title="Click to know more about MAY">MAY</a> proceed through two different mechanisms namely `E_(1) and E_(2)` <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/SUR_CHE_XI_V02_S_MQP_03_E01_040_S01.png" width="80%"/> <br/> (i) The rat of `E_(2)` reaction depends on the concentration of alkyl halide and base Rate =K [alkyl halide] [base] <br/> (ii) It is therefore , a <a href="https://interviewquestions.tuteehub.com/tag/second-1197322" style="font-weight:bold;" target="_blank" title="Click to know more about SECOND">SECOND</a> order reaction. Generally primary alkyl halide <a href="https://interviewquestions.tuteehub.com/tag/undergoes-1436539" style="font-weight:bold;" target="_blank" title="Click to know more about UNDERGOES">UNDERGOES</a> this reaction in the presence of alcoholic KOH. It is a one step process in which the abstraction of the proton from the `beta` carbon and expulsion of halide from the `alpha` carbon occur simultaneously. The mechanism is shown below. <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/SUR_CHE_XI_V02_S_MQP_03_E01_040_S02.png" width="80%"/> <br/> (iii) Generally, <a href="https://interviewquestions.tuteehub.com/tag/tertiary-665438" style="font-weight:bold;" target="_blank" title="Click to know more about TERTIARY">TERTIARY</a> alkyl halide which undergoes elimination reaction by this mechanism in the presence of alcoholic KOH. It follows first order kinetics . Let us consider the following elimination. <br/> Step-1 : Heterolytic <a href="https://interviewquestions.tuteehub.com/tag/fission-991153" style="font-weight:bold;" target="_blank" title="Click to know more about FISSION">FISSION</a> to yield a carbocation <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/SUR_CHE_XI_V02_S_MQP_03_E01_040_S03.png" width="80%"/> <br/> Step-2 : Elimination of a proton from the `beta` - carbon to produce an alkene. <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/SUR_CHE_XI_V02_S_MQP_03_E01_040_S04.png" width="80%"/></body></html>


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