Write the chemical formula for the reactant which behaves like an acid in CaO+H2O Ca2+ + 2 OH-.?

Question

Write the chemical formula for the reactant which behaves like an acid in CaO+H2O Ca2+ + 2 OH-.?

Answer 1

CaO + HOH  ==>  Ca2+  +  2OH-

H2O donates a proton to CaO. So H2O is the acid and CaO (the proton acceptor) is the base.

Answer 2

Another way to look at is that metal oxides like CaO are basic anhydrides, a base without a water molecule.  That makes CaO the base and water (which donates a proton) must be the acid.

CaO + HOH --> Ca2+ + 2OH-

Answer 3

H2O is the acid here.