1,2-Dimethylcyclohexene undergoes only trans-addition with HBr in non-polar solvents but both cis-and trans-additions occur with aq. Acid. Explain.

1,2-Dimethylcyclohexene undergoes only trans-addition with HBr in non-

1.	1,2-Dimethylcyclohexene undergoes only trans-addition with HBr in non-polar solvents but both cis-and trans-additions occur with aq. Acid. Explain.
Answer» <html><body><p></p>Solution :This sterospecific reaction proceeds through a bridged cation like the bromonium ion where `H` replaces `Br`. The intermediate may actually be a `pi` -complex. In the absence of a solvent that can satbilise a <a href="https://interviewquestions.tuteehub.com/tag/free-465311" style="font-weight:bold;" target="_blank" title="Click to know more about FREE">FREE</a> `R^(oplus), Br^(Ө)` attacks the protonated complex from the opposite side resulting in trans (anti) addition. <br/> In the case of a <a href="https://interviewquestions.tuteehub.com/tag/polar-1157435" style="font-weight:bold;" target="_blank" title="Click to know more about POLAR">POLAR</a> solvent such as `H_2 O`,the protonated complex collapses to the free `R^(oplus)`, which now <a href="https://interviewquestions.tuteehub.com/tag/reacts-1178303" style="font-weight:bold;" target="_blank" title="Click to know more about REACTS">REACTS</a> from both sides (faces) and gives both `<a href="https://interviewquestions.tuteehub.com/tag/cis-408731" style="font-weight:bold;" target="_blank" title="Click to know more about CIS">CIS</a>-` and trans-additions. <br/> <img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/KSV_ORG_P1_C05_S01_052_S01.png" width="80%"/>.</body></html>