The coefficients in a chemical equation represent the molar ratio of the substances.
For example, if an equation says 2H2 + O2 ⇒ 2H2O, it means
2 moles of H2 + 1 mol of O2 ⇒ 2 moles of H2O.
I believe the answer you are looking for is the 4th one.
1) acid
2) ether
3) ester
4) aldehyde
5) ketone
6) amine
7) alcohol
El agua con hielo es sistema heterogénea .