Author Topic: Organic Chemistry  (Read 5901 times)

Offline sciencefan

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Organic Chemistry
« on: October 11, 2010, 05:26:24 am »
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...

« Last Edit: October 11, 2010, 05:37:11 am by sciencefan »

Offline Deadly_king

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Re: Organic Chemistry
« Reply #1 on: October 11, 2010, 06:00:19 am »
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 :)
« Last Edit: October 11, 2010, 06:03:54 am by Deadly_king »

Offline sciencefan

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Re: Organic Chemistry
« Reply #2 on: October 11, 2010, 06:22:52 am »
Thanks to answer me Deadly_king,,

Ok but why the propanol structure is not like this;



                 c=c-c- ( is an isomer)????????
                 of
                this
               c-c-c
« Last Edit: October 11, 2010, 06:25:04 am by sciencefan »

nid404

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Re: Organic Chemistry
« Reply #3 on: October 11, 2010, 06:23:24 am »
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.




Offline sciencefan

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Re: Organic Chemistry
« Reply #4 on: October 11, 2010, 06:30:46 am »
Thanks you mr/mrs

Your answer is very precious ;)

Offline Deadly_king

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Re: Organic Chemistry
« Reply #5 on: October 11, 2010, 07:35:13 am »
Thanks to answer me Deadly_king,,

Ok but why the propanol structure is not like this;



                 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 :)
« Last Edit: October 11, 2010, 07:44:44 am by Deadly_king »

Offline sciencefan

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Re: Organic Chemistry
« Reply #6 on: October 11, 2010, 09:07:07 am »
Another question..

When ethene reacts with HCl the products is chloroethene + HCl  ?

« Last Edit: October 11, 2010, 09:11:59 am by sciencefan »

nid404

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Re: Organic Chemistry
« Reply #7 on: October 11, 2010, 09:13:19 am »
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

Offline Deadly_king

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Re: Organic Chemistry
« Reply #8 on: October 11, 2010, 09:14:10 am »
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.

nid404

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Re: Organic Chemistry
« Reply #9 on: October 11, 2010, 09:16:59 am »
Yup true that King  :)
It's an electrophilic addition reaction. So both of them add across the double bond

Offline Deadly_king

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Re: Organic Chemistry
« Reply #10 on: October 11, 2010, 09:19:01 am »
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 ;)

nid404

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Re: Organic Chemistry
« Reply #11 on: October 11, 2010, 09:19:56 am »
Indeed.....but I don't think you need to know all that for O-level ;)

Oh yeah...didn't....notice....:P

Offline sciencefan

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Re: Organic Chemistry
« Reply #12 on: October 11, 2010, 09:28:34 am »
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.


nid404

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Re: Organic Chemistry
« Reply #13 on: October 11, 2010, 09:37:54 am »
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.



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.


Offline sciencefan

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Re: Organic Chemistry
« Reply #14 on: October 11, 2010, 09:45:51 am »
All is clear now  ;D

Thanks you everybody.. ;) ;) ;) ;) ;) ;) ;) ;) ;)