Hclo is a weak acid (ka=4.0x10^-8) and so the salt naclo acts as a weak base. what is the ph of a solution that is 0.037 m in naclo at 25 c

Given:

Concentration of NaClO = 0.037 M

ka (HClO) = 4.0*10⁻⁸

To determine:

The pH of the NaClO solution

Explanation:

The hydrolysis of the weak base can be represented by the ICE table shown below-

ClO - + H2O ↔ HClO + OH-

Initial 0.037M 0 0

Change - x + x + x

Equilibrium (0.037-x) x x

kb = kw/ka = [HClO][OH-]/[ClO-]

10⁻¹⁴/4*10⁻⁸ = x² / (0.037-x)

x = [OH-] = 9.62*10⁻⁵

p[OH-] = - log[OH-] = - log [9.62*10⁻⁵] = 4.02

pH = 14-p[OH-] = 14 - 4.02 = 9.98

Ans: pH of the solution is 9.98