Why would solution iv be considered the most concentrated base out of the four substances?

it has the highest concentration of hydrogen ions.
it has the highest concentration of hydronium ions.
it has the highest concentration of oxide ions.
it has the highest concentration of hydroxide ions.

Solution IV has to be considered the most concentrated base out of the four substances because:

It has the highest concentration of oxide ions.

Explanation:

The reason behind the answer is because oxide ions contain more electrons than ions that are not oxidized. The reason is because of the nature of the covalent bonds and the attraction of electrons in atoms. They tend to jump from the atom with a less positive charge to the one that has a bigger positive charge. In this case, the electrons create a negatively charged oxygen atom that will preserve them until an atom with more positive energy is in contact with it.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.