10pOH

10pOH is not a standard term, but it can be understood as a pOH value of 10. pOH is the negative base-10 logarithm of the hydroxide ion activity: pOH = -log10[OH−]. It is a complementary measure to pH, and together they relate to the water autoionization constant by pH + pOH = pKw, where pKw depends on temperature.

Interpreting pOH = 10: this means [OH−] = 10^−10 M. At 25 °C, where pKw ≈ 14, the corresponding pH would be pH = pKw − pOH = 14 − 10 = 4. Thus a solution with pOH = 10 is acidic overall, as indicated by its pH of about 4 under standard room-temperature conditions. In general, a higher pOH indicates a lower hydroxide concentration and a more acidic or less basic solution, whereas a lower pOH indicates higher hydroxide concentration and a more basic solution.

Temperature dependence: pKw is temperature dependent, so the relationship pH + pOH = pKw is valid at a given temperature but the numeric value of pKw changes with temperature. Consequently, the same pOH value can correspond to different pH values if the temperature is different from 25 °C.

Practical notes: pOH is commonly used alongside pH in aqueous chemistry to characterize basicity and alkalinity. In neutral pure water at 25 °C, both pH and pOH are about 7. Deviations from neutrality reflect the presence of acids or bases, which shift the balance between [H+] and [OH−].