Question

What is the hydronium-ion concentration of a 0.0085 M NaOH solution?

Answer 1

As NaOH is very strong electrolyte ,it will completly dissociate into its constituent ions

NaOH(aq) --------------> Na⁺(aq) + OH^-(aq)

0.0085M will give 0.0085M 0.0085 M   

hydronium ions = H₃O⁺

we know that pOH = -log[OH^-] = -log[0.0085M] = 2.07

pH + pOH = 14

pH = 14-2.07 ~12

pH = -log[H⁺] = 12

[H⁺] = 1.1764706 x 10^-12 M

I really sorry but in place of log i took ln(natural log) that is why there was difference in answer

also for any solution at STP

[H₃O⁺] x [OH^-] = 10^-14

[H₃O⁺] = 10^-14 / 0.0085 = 1.1764706 x 10^-12

thanks please upvote if helpful