Which description correctly characterizes the acidity or basicity of a solution? the higher the ph is, the more the hydroxide ion concentration decreases and the more acidic the solution becomes. the higher the ph is, the more the hydroxide ion concentration increases and the more basic the solution becomes. the lower the ph is, the more the hydronium ion concentration decreases and the more acidic the solution becomes. the lower the ph is, the more the hydronium ion concentration increases and the more basic the solution becomes.