How does the ph of hydrochloric acid change when copper oxide is graduallt added to hydrochloric acid until excess? does it increase? decrease?

Copper does not react with HCl acid, but copper oxide does react. A metal-acid reaction is always a redox reaction. Since copper has a higher reduction potential than hydrogen, it does not react with non-oxidising acids like HCl or dil.H2SO4.

c u c l 2 + 2 n a n o 3 → c u ( n o 3 ) 2 + 2 n a c l

  long weird answer but i hope this works

u i forgot the answer?