The concentration of [OH-] -hydroxide ion : 1.2 x 10⁺⁴ M
Further explanation
H₂O ionization reaction
2 H₂O ⇌ OH− + H₃O⁺
The water equilibrium constant (Kw) is the product of concentration
the ions:
Kw = [H₃O +] [OH-]
Kw value at 25° C = 10⁻¹⁴
It is known [H₃O +]=8.4 x 10⁻¹¹ M
then the concentration of [OH-] -hydroxide ion :
![\tt 10^(-14)=8.4* 10^(-11)* [OH^-]](https://img.qammunity.org/2021/formulas/chemistry/high-school/h4gz1q0s91ysa3u6381yhkcc5lo0sonzgz.png)
![\tt [OH^-]=(10^(-14))/(8.4* 10^(-11))=1.19* 10^(-4)\approx 1.2* 10^(-4)](https://img.qammunity.org/2021/formulas/chemistry/high-school/zo4z3wtwjscld9ijs970qga7yomo166xdv.png)