Organic Chemistry

[Anomaly]

Can somebody please tell me... when we react say aq. Bromine with 4-Aminomethybenzene, do the Br groups join the ring relative to the Amino group or the Methyl Group? (both are 2,4 directing groups)

 

[princesszahra]

due to both!!!!
there's a question like this in p4 chem recent years
but there is some problem with the groups u've chosen
i mean one has to be meta directing ( 3 , 5) and one ortho and para (2,4)!

 

[Anomaly]

due to both!!!!
there's a question like this in p4 chem recent years
but there is some problem with the groups u've chosen
i mean one has to be meta directing ( 3 , 5) and one ortho and para (2,4)!

Whats wrong with the groups? 2 Ortho directing groups cant appear? eg. 4-Aminophenol?

 

[mariam]

can somebody plz help me with this question??
chem p4 part (c) (i) and (ii)

 

[princesszahra]

ohoo @ stuck which year?

 

[mariam]

oops sorie june 07

 

[princesszahra]

ohoooooooooo again
which question stuck!

 

[mariam]

lol....!
june 07 Q4 part c (i)(ii)

 

[PlanetMaster]

It would be 'C' because of lower wavelength.

 

[mariam]

but how is C red and D blue??

 

[Dara]

@stuck: the table given to us is for absorbance.
C is red and D is blue because OBSERVE colours are complementary to the colour absorb.
i hope u get it.

 

[mariam]

no..! can u plz explain it to me?? :?

 

[Anomaly]

but how is C red and D blue??

The color which is least absorbed is the one transmitted i.e seen.Check the wavelength from the graph, which is the least absorbed and check color from the table given

 

[Dara]

oh sure ill try, coz im not at all gud at explaining :?
see v are given a table and a graph.
from graph v see d wavelength with d highest absorbance which is 450-500nm for C and 650nm for D.
Checking these values from the table the colours v get are blue for C and red for D,
but as i told u earlier these are absorbed colour and v r being asked for the observed colour
which is COMPLEMENTARY to d one absorbed.
Therefore, C is red and D is blue.

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"Reach high, for stars lie hidden in your soul. Dream deep, for every dream precedes the goal."

 

[mariam]

ohh..!
i got it now..!
thanks alot..!

 

[Dara]

hmm...dats great
ur welcome.
-------------------------------------------------------------------------------
"Reach high, for stars lie hidden in your soul. Dream deep, for every dream precedes the goal."

 

[mariam]

what do we have to learn in xray crystallography? :roll: i dunt understand it at all

 

[mak]

okk okkk thanx... but i din get why are they complementary to each other ?? for example if there was just one graph give lets say... C nd nO D... then which colour would b observed ???

 

[mak]

plzzzzzzzzz