How will a solution change if a base is added? The hydroxide ion concentration will decrease and lower the pH.
The hydroxide ion concentration will decrease and raise the pH.
The hydrogen ion concentration will increase and lower the pH.
The hydroxide ion concentration will increase and raise the pH.

As the concentration of hydrogen ions in a solution increase, the more acidic the solution becomes. As the level of hydroxide ions increases the more basic, or alkaline, the solution becomes. ... Thus, as the hydrogen ion concentration increases hydroxide ion concentration falls, and vice versa.

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the answer is c

explanation:

halogen, any of the six nonmetallic elements that constitute group 17 (group viia) of the periodic table. the halogen elements are fluorine (f), chlorine (cl), bromine (br), iodine (i), astatine (at), and tennessine (ts).