Well,

All elements in positive oxidation states begin their existence in water as hydrated cations and then undergo reactions between the cations and the water to "neutralize" their positive charge. These reactions ultimately alter the pH of the solution.

https://www.wou.edu/las/physci/ch412/redox.htm

Regards

Thank u bayanji,

If Redox potential increase, pH decrease/increase??

Well,

may be decreased and may increase according to type of reaction, for example, see the attached fig.

Regards

Thank u bayanji

I agree with Bayan Hussien sir.