Question

Which functional group is not found in gingerol, the flavor component in fresh ginger? Aldehyde, ketone, ether, alcohol, or aromatic ring?

Answer 1

I have drawn the structure of Gingerol below using a chem draw.

Now lets think about the functional groups given in the question and how to identify them.

1) Aldehyde

Aldehyde functional group is signified as a -CH=O group (written simply as -CHO). In this fucntional group a carbon is attached to an oxygen with a double bond as well as to a hydrogen with a single bond. As a carbon atom can only make 4 bonds in total, aldehyde groups are only found at the end of a carbon chain.

As you can see from the structure, there is no aldehyde group in there

2) Ketone

Ketones (C3H-C(CH3)=O) are very similar to aldehydes except that they involve a carbon attached to an oxygen with a double bond and the other two bonds of this carbon are formed with carbon itself. Since this group is by definition surrounded by to carbon atoms, it is always found somewhere in the middle of a carbon chain.

In the strcuture above atoms 11,12,13,& 15 form the ketone group

3) Ether

The ether group corresponds to an oxygen atom sitting between two carbon atoms bonded to both with a single bond. (CH3 - O - CH3).

In the structure above atoms 4, 7, 8 form the ether group

4) Alcohol

The Alcohol group is represented by one oxygen atom directly bonded to one carbon atom and one hydrogen atom. (CH3 - O - H).

In the structure above atoms 3 and 9 form the alcohol group.

5) Aromatic ring

An Aromatic ring is a cyclic structure with total number of pi electrons = 4n+2 where n can be any integer from 1,2,3 ......

in the structure above atoms 1:6 form a cyclic stucture which has 6 pi electrons (3 double bonds).

4(1)+2 = 6

this fits into the 4n + 2 form with n=1, thus this ring is aromatic