functional group

[braddy]

Hi ,

Please can someone help me this this.

When FeCl3 reacts with salicylic acid, the solution turns purple.

-With with part of the molecule (sacilylic acid) does the FeCl3 react?

Thank you for your help.

Braddy

[RobJim]

I'll start you out on this.

FeCl3 looks like an ionic compound, made of Fe(3+) and 3 Cl(-) ions.

You can find the structure of salicylic acid on chemfinder.com. It's a phenyl ring ortho- substituted with an acid group and a hydroxy group.

http://chemfinder.cambridgesoft.com

The reaction will take place with either the iron ion or the chlorine ion interacting with the acid group on the salicylic acid molecule. There are four atoms on the acid group: the carbon, the hydroxy oxygen, the double bonded oxygen, and the hydrogen. One of the ions will form a bond with one of the atoms in the acid group. Think about it for a bit.

[braddy]

Thank I got it . I see what to do now..

Braddy

[charco]

Iron III chloride reacts with the OH group attached to a benzene ring (i.e. a phenol) giving a purple complex. This is used as a test for the phenol grouping.

It's likely nature is that of a coordinated complex with phenol species doubly coordinated to the Fe3+ ion using the oxygen and the electrons in the delocalised ring system.

[RobJim]

Really? Oops. I hope I didn't lead braddy in the wrong direction. :oops: