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### Topic: Problem of the week - 24/09/2012  (Read 27018 times)

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#### Borek

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##### Problem of the week - 24/09/2012
« on: September 24, 2012, 08:01:23 AM »
Simple alkene, gaseous at RTP, reacts with a highly toxic red-brown gas producing a chiral compound that contains 21.17% 20.68% of chlorine. Very similar compound, with a lower molar mass but higher percent chlorine content, is optically inactive. Identify the alkene and the gas.
« Last Edit: September 26, 2012, 08:07:50 AM by Borek »
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#### fledarmus

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##### Re: Problem of the week - 24/09/2012
« Reply #1 on: September 26, 2012, 07:42:57 AM »
I believe I've identified the gas, I have the empirical formula for the first compound, and I can't come up with a structure that matches the formula.

#### Borek

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##### Re: Problem of the week - 24/09/2012
« Reply #2 on: September 26, 2012, 08:15:35 AM »
Sigh. I hate myself. I did some stupid mistake again and in a place where I would never expect it  And while I would understand many other errors, I don't understand where this one came from. I need either new glasses or new brain. Or both.

Try now, with the corrected percentage. Sorry for wasting your time
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#### fledarmus

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##### Re: Problem of the week - 24/09/2012
« Reply #3 on: September 26, 2012, 11:49:16 AM »
It's all good

New empirical formula, I have two possibilities for the gas, my only question now is what counts as "very similar"?

#### Borek

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##### Re: Problem of the week - 24/09/2012
« Reply #4 on: September 26, 2012, 01:30:31 PM »
Similar in terms of similar reagents and similar reaction
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#### Borek

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##### Re: Problem of the week - 24/09/2012
« Reply #5 on: September 29, 2012, 04:49:47 AM »
Still too hard? Or is there still something wrong with the problem and you can't solve?
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#### discodermolide

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##### Re: Problem of the week - 24/09/2012
« Reply #6 on: September 29, 2012, 05:16:41 AM »
OK I'll stick my neck out.
But-1-ene and the gas is BrCl. But I am not aware of it's colour, I guess brownish.
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#### CrazyAssasin

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##### Re: Problem of the week - 24/09/2012
« Reply #7 on: September 29, 2012, 07:05:16 AM »
Yes, I get the same answer.

#### Dan

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##### Re: Problem of the week - 24/09/2012
« Reply #8 on: September 29, 2012, 09:08:51 AM »
I guess (E)-but-2-ene. Reaction with BrCl produces racemic (2R,3S)-3-bromo-2-chlorobutane, whereas reaction with chlorine produces (2R,3S)-2,3-dichlorobutane (which is optically inactive (meso) and has a lower MW and higher Cl content).
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#### Borek

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##### Re: Problem of the week - 24/09/2012
« Reply #9 on: September 29, 2012, 09:18:20 AM »
I guess (E)-but-2-ene. Reaction with BrCl produces racemic (2R,3S)-3-bromo-2-chlorobutane, whereas reaction with chlorine produces (2R,3S)-2,3-dichlorobutane (which is optically inactive (meso) and has a lower MW and higher Cl content).

And that's the correct answer, or at least the one I was waiting for

Perhaps instead of "Very similar compound" I should write "Very similar compound, produced from the same alkene".
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#### curiouscat

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##### Re: Problem of the week - 24/09/2012
« Reply #10 on: September 29, 2012, 12:24:50 PM »
But-1-ene and the gas is BrCl. But I am not aware of it's colour, I guess brownish.

#### maugeredson

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##### Re: Problem of the week - 24/09/2012
« Reply #11 on: May 06, 2013, 02:52:23 PM »