If a base is added to water, what will occur?
hydronium ion concentration is increased.
hydroxide ion concentration is decreased.
[h+] is decreased.
[oh-] is decreased.

C

Explanation:

The first and most obvious statement is that [OH-] is increased, but that is not offered to you.

The second most obvious statement is that the [H+] ion is decreased. That is offered to you. It is C

[H+] is decreased.

Explanation:

Arrhenius Theory:

An acid is a substance which produces one or more hydrogen ions, (H+) in aqueous solution.

Examples:

A Base is a substance which produces one or more hydroxyl ion or  hydroxide ion (OH-) in aqueous solution.

Examples

Please note:

(aq) stands for aqueous which means in the presence of water that is, water  acts as a solvent

So, on adding a base to the water increase in will take place and this will decrease the Hydrogen ion concentration  

Pure water contains

if the solution is acidic

if the solution is Basic

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