Question

How would i answer this???

Answer 1

Well, for starters you would draw out the acid with appropriate numbering and substitution....

Explanation:

You gots a `"pentanoic acid derivative..."`:

`HO_2stackrel(1)Cstackrel(2)CH_2stackrel(3)CH_2CH_2stackrel(5)CH_3`

And we number from the carboxyl end....and we substitute the appropriate positions with ethyl and iodo functionalities....

`HO_2stackrel(1)Cstackrel(2)CH(C_2H_5)stackrel(3)CHICH_2stackrel(5)CH_3`

Do you follow? If so, how many geometric isomers would this beast generate?

And now let's address the questions...

`"the parent name is 3-iodopentanoic acid"`...probably wrong...

`"it has 2 ethyl and 3 iodo groups"`...well it has 2 ethyl and ONE iodo group, SO WRONG.

`"it has one halogen and one methyl group"`...clearly it have got TWO methyl groups...one at the terminus, and one on the ethyl group....so WRONG.

`"it is a carboxylic acid"`...I can agree with this...

`"it contains 7 carbons"`...I can agree with this...

Do you agree with this treatment...

Answer 2

You would check Options 4 and 5.

The structure of 2-ethyl-3-iodopentanoic acid is

Let's examine each of the statements in turn.

1. The parent name is 3-iodopentanoic acid

FALSE The parent name is pentanoic acid.

2. It has two ethyl groups and three iodo groups

FALSE The numbers indicate the positions of the groups on the carbon chain. We use multiplying prefixes (di-, tri-, etc.) to show how many there are of each group.

3. It has only one halogen and one methyl group

FALSE It has one halogen and two methyl groups.

4. It belongs to the carboxylic acid functional group because of the ending -oic acid

TRUE If "they" give you the name first, the structure must include a carboxylic acid functional group.

5. It contains a total of seven carbon atoms

TRUE There are five carbon atoms in the main chain and two in the sidechain.