Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Problem of the Week Archive => Topic started by: Borek on September 24, 2012, 08:01:23 AM
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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.
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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.
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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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It's all good :D
New empirical formula, I have two possibilities for the gas, my only question now is what counts as "very similar"?
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Similar in terms of similar reagents and similar reaction :P
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Still too hard? Or is there still something wrong with the problem and you can't solve?
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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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Yes, I get the same answer.
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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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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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But-1-ene and the gas is BrCl. But I am not aware of it's colour, I guess brownish.
(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2Fe%2Fe2%2FBrCl.jpg&hash=abdcdef5d0ed9baf948bfce71fc4a9463db64875)