Identify the option that is not a characteristic of esters:

1.they are prepared by reacting acids with alcohols.

2.they each contain a carbonyl group with an attached oxygen atom that is bonded to a carbon substituent.

3.they are responsible for the odors and flavors of many flowers, perfumes, and ripe fruits.

4.they are prepared by reducing alcohols or aldehydes whose -oh functional group is located on the carbon atom in the middle of the carbon chain.

Option 4 is not the characteristics of esters

Explanation:

Esters :

They are organic compound derived from an organic or inorganic acid. in which one Hydroxyl (OH) group is replaced by an organic alkoxy (-O-R) group.

General formula of Esters:

Easter can be represented by a general formula that is

                                       RCOOR

where R is any alkyl group

No to look at the characteristics of the Esters an find out the odd one option that is not correct.

Option 1 is the characteristics of esters.

Esters are obtained from the reaction of carboxylic acid and an alcohol.

          CH₃COOH + CH₃OH > CH₃COOCH₃ + H₂O

Option 2 is the characteristics of esters.

This option is also correct as if we see at its general formula

The carbonyl group attached to an Oxygen atom and this oxygen is attached to carbon of alkyl group

                                  O==COR

Option 3 is also the characteristics of esters

The odors and flavors of many flowers, perfumes, and ripe fruits is due to the presence of ester. as ester have now hydrogen bonding and low vapor pressure and highly volatile that's why it is responsible for odors.

Option 4 is not the characteristics of esters

This option is wrong, as the carbon atom in the middle of the carbon chain can not be easy to replace, also the carbonyl carbon is directly attached to oxygen group and not Carbon group.