IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => GCE O - Level => Sciences => Topic started by: sciencefan on October 11, 2010, 05:26:24 am
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Hi,,
The results of test on compound X are here: http://farm5.static.flickr.com/4131/5070035943_41e9a38176.jpg
Please give me the answer and also I need to know what is the name of compound C and D ???
Thanks in advance...
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Hi,,
The results of test on compound X are here: http://farm5.static.flickr.com/4131/5070035943_41e9a38176.jpg
Please give me the answer and also I need to know what is the name of compound C and D ???
Thanks in advance...
C : Propan-1-ol
D : 1-Butenoic acid
The question now :
X decolorises bromine water ----> It is alkene,i.e, it contains a double bond ( C=C )
X releases carbon dioxide upon reaction with aqueous sodium carbonate ---> An acidic group is likely to be present.
Hence this eliminates A and B.
However alcohols do not react with carbonates.---> eliminates C as well.
Therefore answer is D
NOTE : It is not necessary that you know the names of the different compounds.
Hope it helps :)
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Thanks to answer me Deadly_king,,
Ok but why the propanol structure is not like this;
(http://upload.wikimedia.org/wikipedia/commons/0/08/Propan-1-ol.png)
c=c-c- ( is an isomer)????????
of
this
c-c-c
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Bromine water test is positive- shows double bond to be present.
Carbonate test shows presence of acid.
The compound having both the functional groups is D.
An allyl group is a hydrocarbon group with the structural formula H2C=CH-CH2
So C is allylalcohol or prop-2-en-1-ol
D is 3-butenoic acid
You don't need to know the names though.
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Thanks you mr/mrs
Your answer is very precious ;)
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Thanks to answer me Deadly_king,,
Ok but why the propanol structure is not like this;
(http://upload.wikimedia.org/wikipedia/commons/0/08/Propan-1-ol.png)
c=c-c- ( is an isomer)????????
of
this
c-c-c
Sorry dude.......C is not propanol. It is propen-1-ol like Garfield said :)
I described B instead of C. :-[
An isomer is a compound with same molecular formula but different structural formula.
A compound consisting a double bond (C=C) will NOT have the same formula as that of hydrocarbon(C-C).
Example : Propene and propane
Propene ----> H2C=CHCH3
Propane ----> H3CCH2CH3
You will note that Propane has two hydrogen atoms more than propene. Hence they are not isomers ;)
By the way.......thanks for correcting me Garfield :)
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Another question..
When ethene reacts with HCl the products is chloroethene + HCl ?
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Another question..
When ethene reacts with HCl the products is chloroethene + HCl...
Nope it's Chloroethane
H H H H
| | | |
H-C=C-H + HCl---> H-C-C-H
| |
H Cl
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Another question..
When ethene reacts with HCl the products is chloroethene + HCl ?
Nan.......When ethene reacts with HCl, only chloroethane is formed!
The C=C breaks and one carbon atom accepts a Cl atom while the other one accepts the H atom.
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Yup true that King :)
It's an electrophilic addition reaction. So both of them add across the double bond
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Yup true that King :)
It's an electrophilic addition reaction. So both of them add across the double bond
Indeed.....but I don't think you need to know all that for O-level ;)
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Indeed.....but I don't think you need to know all that for O-level ;)
Oh yeah...didn't....notice....:P
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I scanned this part in my book, you can read that chloroethene can produce by adding HCl in ethene...
I approuve your answer but confuse.
(http://farm5.static.flickr.com/4088/5071186834_2a44b4740d.jpg)
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I scanned this part in my book, you can read that chloroethene can produce by adding HCl in ethene...
I approuve your answer but confuse.
(http://farm5.static.flickr.com/4088/5071186834_2a44b4740d.jpg)
Thermal cracking of Chloroethane produces Vinylchloride(chloroethene).
They mentioned Chloroethene because it's Industrially more important as compared to Chloroethane. You must remember it is obtained by thermal cracking of the initial product-chloroethane.
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All is clear now ;D
Thanks you everybody.. ;) ;) ;) ;) ;) ;) ;) ;) ;)
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Thermal cracking of Chloroethane produces Vinylchloride(chloroethene).
They mentioned Chloroethene because it's Industrially more important as compared to Chloroethane. You must remember it is obtained by thermal cracking of the initial product-chloroethane.
I don't think you really need to know how chloroethene is obtained.
You just need that chloroethene which is a derivative of ethene is an important compound used in PVC, which is very common in our lives.
That is one of the different uses of ethene. You should limit yourself to this for now ;)