Question

A sample of pure water is heated to a temperature of 112 C at a pressure of 20 MPa, where the ionization constant for water is 4.0 x 10­12. What is the OH ­concentration in the pure water at these conditions?

Answer 1

`[OH^-]^2=2.0* 10^(6)`

Step-by-step explanation:

The ionization constant of the water =
`4.0* 10^(12)` at a temperature of
`112\ ^0C` and pressure of 20 MPa

Water dissociates as;

`H_2O\rightleftharpoons H^++OH^-`

The expression for the ionization constant is :

`K_w=[H^+][OH^-]`

For pure water,

`[H^+]=[OH^-]`

So,

`K_w=[OH^-]^2`

`[OH^-]^2=4.0* 10^(12)`

The concentration of the hydroxide ions,
`[OH^-]^2=2.0* 10^(6)`.