Now, what exactly do we mean by an acidic solution? And what exactly do we mean by a basic solution? So an acidic solution is a solution in which the concentration of the hydrogen ion in solution is greater than the concentration of the hydroxide ion. So we know if this is equal to this, then this is a neutral solution. But an acidic solution is a solution in which this concentration is greater than this concentration. Now for example, let's suppose we know that the concentration of the H plus ion of our solution is equal to 1.0 times ten to negative six.