Added: 1 year ago
From: khanacademy
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  • Can someone explain this? I thought that if that positive-charged carbon anion is getting more negative charge from the surrounding carbons, wouldn't that make it less positively charged? So if it's less positively charged, wouldn't the Bromide not attach itself to it as much?

  • Markovnikov Rules

  • Gracias.

  • I am the first person to dislike this video

  • @goldensilverstar And why is that? O_o

  • Shouldn't the arrow be only a half arrow since you are only transferring one electron rather than electron pair?

  • @chillerman625 haha i actually asked this question too on a different vid......i just went with the flow and ignored it

  • @chillerman625 @thatguy126 You're right, a barbed curved arrow ("half arrow") should be used when only one electron is moving (e.g. homolytic bond cleavage or radical reactions). Sal talks about moving only one electron here, but the common convention in this mechanism is to depict the movement of pairs of electrons, which would be indicated using a full arrow. So the full arrow is correct for this mechanism, but it should be two, not one, electrons moving in each of the steps.

  • Genial señor, thanks

  • where have you been all my life?! this was so helpful! you are awesome!!! yay! :D

  • So, what I can see here is that the more stable the carbocation, the more it tendency to be bonded with H+, am I right? :\

  • Thank you so much! I'm planning to take ochem this coming semester, and I hope I can watch all your videos before school starts! :D

  • Thanks Salman.

  • I love you even more. I'm Indian too btw xD

  • I love you

  • I love you

  • This is a dumb question but when you said stable did you mean that the valence electrons were filled?

  • @O0oSorousho0O Yes.

  • @O0oSorousho0O Yes, when the valence shell is filled.

  • This summer, I will try to watch every single Khanacademy video! I hope! :D

  • great visuals! wish you could have been my ochem prof back in college.

  • this stability video has no significance but justy confuses.......

    just break the double bond so we get two posibilies ie the presence of partially positive on one or the other and we know the order of the stability of carbocation ie positive charge which is resonance>3deg>2deg>1deg>0deg

  • Great pedagogics, voice and visual assets! Very helpful, thank you and keep up the good work!

  • Markovnikov sounds like a capitalist. Rich get richer, poor get poorer.

  • Are you single?

    just kidding. Thank you so much for your help.

  • Quick question Sal (or anyone else): should Sal not draw a single arrowhead instead of ----> because ---> implies that there are two electrons being lost from an atom but in this mechanism we are seeing only one electron at a time being moved from one atom to anotehr. Anyone want to clarify this? thanks.

  • "Borrow electrons from some of its friends" HAHAHAHA

  • lovely! :D....and all of this occurs at room temperature...right o_O? ....please dooo a video on oxidation of alcoholssssssss!!!!!!!!!!!! thanks :)

  • I wonder .. the right carbon in left compound was attached to 3 carbons ..

    does that right carbon call tertiary carbon ?

  • You make all this stuff very simple to understand! Thank you!

  • Wait, what if the second carbon (in the left) was bonded to a electron hogging group like chlorine? I don't see a reason for the left mechanism to work at all (without peroxides), but I know I'm wrong. Help?

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  • @n1a1s1i1m I believe the left one works because it has two carbon groups to stabilize the positively charged transition state whereas the one on the right doesn't work as well because it only has one carbon group. This means that the one on the left has a lower energy hurdle to jump over so it is more likely to occur.

    I'm not sure if that is what you mean? Either way, your post is a year old so you probably don't even care anymore.

  • @n1a1s1i1m A year later..

    Its not bonded to a Cl, the point is that the H goes to the place where MOST of the H are bonded. The C-HH to make C-HHH.

    Or you can look at the carbons and see which one has the higher carbocation (In this case, it was secondary). We know carbon can have tertiary, secondary, and primary. In this example there is no tertiary so look at the secondary one.

  • Swiper no swiping?

  • Sal, I am addicted to these videos.

  • This one actuality has great quality video, thanks SAL for the hard work !

    I'm from Algeria and u just helped me alot to understand Math and Chemistry ... Thx again :)

  • Twice the same video, Sal?

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