So at a PH of seven, our concentration of hydronium equals that of hydroxide. Now, at any given temperature, the ionization constant will always remain the same. So at 25 degrees Celsius, this guy will always be 1.0
times ten to negative 14. This will only increase with increase in temperature or decrease with decreasing temperature. This does not depend on the concentration of this guy, nor on this guy. Now, if our hydronium concentration is greater than 1.0 times ten to negative seven, that means our solution is acidic.