Multiple choice A base is a compound that ______ the number of ____(_) when dissolved in water. Decreases, Hydroxide, H+ Increases, Hydrogen, H+ Increases, Hydroxide, OH- Decreases, Hydrogen, OH- Reveal answer Fill a bubble to check yourself C Correct answer Explanation By the Arrhenius definition, a base increases the concentration of hydroxide ions (OH-) in an aqueous solution.