Question

Which of the following represents the ester functional group?

A. -COO-
B. -CHO
C. -COOH
D. C=O

Answer 1

D. C=O

Step-by-step explanation:

Esters are formed by the condensation of alcohols and acids with minus water. During the reaction, at least one -OH group is replaced by an O- alkyl group. The resulting compound is an ester and has a characteristic fruity smell. Its functional group is C=O

Answer 2

Answer: A. -COO-

Step-by-step explanation:

Functional groups are specific group of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.

A. Esters have functional group
`-O=C-OR`.

Example: methyl ethanoate with molecular formula
`CH_3COOCH_3`

B. Aledydes have functional group
`-O=CH`.

Example: Ethanal with molecular formula
`CH_3CHO`

C. Acids have functional group
`-O=C-OH`.

Example: Ethanoic acid with molecular formula
`CH_3COOH`

D. Ketones have functional group
`-C=O`.

Example: Propanone with molecular formula
`CH_3COCH_3`