Final answer:
In a double replacement reaction, Cu(OH)2 reacts with HClO4 to form Cu(ClO4)2 and H2O. The balanced equation is Cu(OH)2(s) + 2HClO4(aq) -> Cu(ClO4)2(aq) + 2H2O(l).
Step-by-step explanation:
To complete and balance the molecular equation Cu(OH)2(s) + HClO4(aq) --> ???, we need to determine the products of the reaction.
This is a double replacement reaction, where the Cu(OH)2 reacts with HClO4 to form new compounds. The products will be Cu(ClO4)2 and H2O. The balanced equation for the reaction is Cu(OH)2(s) + 2HClO4(aq) --> Cu(ClO4)2(aq) + 2H2O(l).