Why the pH value does not change?

[Johnny Leong]

When the CuO (copper oxide) is put into water, it does not dissolve in water. But why the pH value of the water does not change?

[Zargawee]

pH of a solution is measured by H3O+ concentration , therefore , the value of the water won't change cause no H3O+ were added or taken .

[Monique]

pH might change due to a redox reaction, catalyzed by the metal, but you say it doesn't dissolve, so no reaction is taking place (with dissolve I mean ions coming free).