Question

Copper (II) oxide is a:
(A) Weak acid
(B) Weak base
(C) Strong acid
(D) Strong base

Answer 1

Hint: As we know that there are 3 types of compounds or substances that are acid, base and neutral. These acid and base compounds can further be categorized as strong or weak based on their various chemical properties. So here we have to say the same about copper (II) oxide compound which is also known as cupric oxide.

Complete answer:
Let us discuss about acids and bases followed by copper oxide as follows:-
-Acids: These are the substances which donate protons or hydrogen ions when mixed in an aqueous solution. It is a hydrogen containing substance which is capable of donating a hydrogen ion to another compound. These are generally categorized as strong acids and weak acids.
-Strong acids are those which ionize completely in an aqueous solution by losing all the protons whereas weak acid ionizes partially in a solution as it only loses few of its hydrogen ions ($H^{+}$).
 -Base: These are substances which generally accept hydrogen ions or protons. They generally dissociate in the form of hydroxide ions ($O{H}^{-}$). These are also categorized as strong bases and weak bases.
- Strong bases are those which ionize completely in an aqueous solution by losing all the hydroxide ions whereas weak acid ionizes partially in a solution as it only loses few of its ions and rest remains intact.
-Copper (II) oxide: It is also known as cupric oxide and its chemical formula is CuO. It is a black solid compound which acts as a precursor to many other copper containing chemical compounds and minerals.
-Generally oxides of metal are basic in nature whereas oxides of non-metal are acidic in nature. Since copper (II) oxide is a metallic oxide so it is basic in nature.
-When CuO is in aqueous solution, it does not dissociate completely in it which means that it is a weak base. Also when it is dissolved in water, it forms copper hydroxide ($Cu{(OH)}_2$).

Therefore copper (II) oxide is a: (B) Weak base

Note:
-Remember that strong acids and bases have higher conductivity due to complete dissociation whereas weak acids and bases have lower conductivity. Due to this reason we can also categorize it as a weak base because it has low conductivity as well. It also has an approximate 11 pH which shows that it is a weak base.