Calculate the hydronium ion concentration in an aqueous solution with a ph of 9.85 at 25°c. calculate the hydronium ion concentration in an aqueous solution with a ph of 9.85 at 25°c. 1.4 * 10-10 m 4.2 * 10-10 m 7.1 * 10-5 m 6.5 * 10-5 m 8.7 * 10-10 m

Answer is: 1.4 * 10-10 m

pH = 9.85.

[H₃O⁺] = 10∧ (-9.85).

[H₃O⁺] = 1.4·10⁻¹⁰ M.

pH (potential of hydrogen) is a numeric scale used to specify the acidity or basicity an aqueous solution.

If pH is greater than seven, solution is base and if pH is equal seven, solution is neutral and if pH of solution is less than seven, than is acidic.