A liquid shampoo has a hydroxide ion concentration of 6.8x10⁻⁵ mol/l

Question

a) Calculate the hydronium ion concentration

b) What is the pH and pOH of the shampoo?

Answer 1

Recall that [H₃O⁺]OH^-] = 1x10^-14

a) [H₃O⁺] = 1x10^-14 / 6.8x10^-5 = 1.5x10^-10 M

b) pH = -log [H₃O⁺] = - log 1.5x10^-10 = 9.8

pOH = -log [OH^-] = -log 6.8x10^-5 = 5.2

You can also find pOH from the equation of pH + pOH = 14; pOH = 14 - 9.8; pOH = 5.2