Cupric Oxide-Introduction, Preparation, Properties, Uses, Practice Problems, FAQs

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You might have many such designer articles in gift shops and as fashion exhibits. They are designs made with certain colouring pigments on pieces like ceramics, metals, terracotta, etc. The colours are so variant all the possible mixtures of VIBGYOR colours. People lime such beautiful things for decorative purposes.

But, did you ever thought about how these colouring pigments are made?

On this page, you will find from we get such beautiful pigmentations and designs on ceramics. One such colour and the widely used pigment is derived from the element copper and its oxide-namely cupric oxide.

Copper is related to our historic period. Our forefathers realised that copper is malleable, holds a sharp edge, and can be fashioned into tools, ornaments, and weapons more quickly than a stone between 7,000 and 10,000 years ago, a discovery that would impact humanity forever.

Let’s study the important compounds derived from copper i.e, cupric oxide and see how beneficial they are. So come and let’s begin!

TABLE OF CONTENT

Introduction
Cupric oxide- Preparation
Cupric Oxide- Properties and Reactions
Cupric Oxide- Uses
Practice Problems
FrequentlyAasked Questions

Introduction

Copper forms two oxides. CuO is the chemical formula for cupric oxide, also known as copper(II) oxide. It is one of the two stable oxides of copper and black in colour, while the other cuprous oxide with the formula Cu₂O or copper(I) oxide, is a brown solid. Mineral, cupric oxide is known as a tenorite. It is a byproduct of copper mining and a starting point for many other chemical compounds and products that contain copper.

Cupric Oxide-Preparation:

Cupric oxide is a black copper oxide that can be found in nature as Tenorite.

Preparation of Cupric Oxide:

Cupric oxide is prepared by heating Cu₂O in air or heating copper in the air for a long time keeping the temperature, not above 1100℃.

${C u}_{2} O (s) + \frac{1}{2} O_{2} (g) \to 2 C u O (s)$

$2 C u (s) + O_{2} (g) \to 2 C u O (s)$

Cupric hydroxide on heating forms Cupric oxide.

$C u (O H)_{2} (s) \to C u O (s) + H_{2} O (l)$

Heating copper nitrate produces cupric oxide.

$2 C u ({N O}_{3})_{2} (s) \to 2 C u O (s) + 4 {N O}_{2} (g) ↑ + O_{2} (g) ↑$

It's made commercially by heating malachite ore, which is present in nature.

$C u C O_{3} . C u (O H)_{2} (s) \to 2 C u O (s) + C O_{2} (g) ↑ + H_{2} O (l)$

Cupric Oxide- Properties and reactions:

It is a black powder that is stable till mild heating.

The oxide is water-insoluble but dissolves in acids and forms salts.

Mineral acids like hydrochloric acid, sulfuric acid, or nitric acid can be used to dissolve copper (II) oxide and produce the corresponding copper (II) salts.

For example,

$C u O (s) + 2 H C l (a q) \to C u {C l}_{2} (s) + H_{2} O (l)$

$C u O (s) + H_{2} S O_{4} (a q) \to {C u}_{2} S O_{4} (s) + H_{2} O (l)$

$C u O (s) + 2 H N O_{3} (a q) \to C u (N O_{3})_{2} + H_{2} O (l)$

It produces cuprate salts when combined with concentrated alkali:

$2 M O H (s) + C u O (s) + H_{2} O \to M_{2} [C u (O H)_{4}] (s)$

Where M is any alkali metal.

Using carbon dioxide, carbon monoxide, or hydrogen, it can be transformed into copper metal.

$C u O (s) + H_{2} (g) \to C u (s) + H_{2} O (l)$

$C u O (s) + C O (g) \to C u (s) + C O_{2} (g) ↑$

$C u O (s) + C (s) \to C u (s) + C O (g) ↑$

It is transformed to cuprous oxide with the release of oxygen when heated to 1100-1200°C.

$4 C u O (s) \to 2 {C u}_{2} O (s) + O_{2} (g) ↑$

Cupric oxide- Uses:

Copper(II) oxide, a substantial byproduct of copper mining, serves as the raw material for synthesising additional copper salts. For instance, copper oxide is used to make a variety of wood preservatives.
In ceramics, the cupric oxide is used as a pigment to create glazes in the colours blue, red, and green, occasionally grey, pink, or black.
When welding with copper alloys, the cupric oxide is utilised.
It is used to remove sulphur from petroleum.
It is utilised for carbon estimation and detection in organic analysis.

Practice Problems:

Q1._____________ is the oxidation state of Copper in cupric oxide.

A. 0
B. +1
C. +2
D. +3

Answer: C

Solution: Let the oxidation state of copper in CuO be x.

For calculating this we know that the oxidation state of the oxygen we consider is -2.

Now, calculating this we get,

$x + (- 2) = 0$

$\Rightarrow x = + 2$

Hence, +2 is the oxidation state of Copper in CuO.

Q2. Copper (II) oxide when heated with hydrochloric acid, the main product we get are____________.

A. cuprous chloride and hydrogen
B. cupric chloride and water
C. cupric chloride and hydrogen
D. cuprous chloride and water

Answer: B

Solution: Copper (II) oxide when heated with hydrochloric acid, the main product we get are cupric chloride and water. Here is the mentioned reaction.

$C u O (s) + 2 H C l (a q) \to C u {C l}_{2} (s) + H_{2} O (l)$

Q3. In the following reaction $C u O (s) + H_{2} (g) \to C u (s) + H_{2} O (l)$

___________ substance is oxidised and ________substance is reduced

A. Cu and H₂ respectively.
B. H₂ and Cu respectively.
C. H₂ and H₂O respectively.
D. CuO and H₂ respectively.

Answer: B

Solution: A chemical reaction known as an oxidation-reduction (redox) reaction includes the exchange of electrons between two substances. In a redox reaction, an electron is either gained or lost, changing the oxidation number of a molecule, an atom, or an ion.

$C u O (s) + H_{2} (g) \to C u (s) + H_{2} O (l)$

in the reaction H₂ is oxidised since it has lost electrons and Cu is getting reduced since it has gained electrons.

Q4. Heating malachite will release ___________ gas.

A. H₂
B. CO₂
C. CO
D. O₂

Answer: B

Solution: Cupric oxide is made on a commercial basis by heating malachite, which is present in nature.

$C u C O_{3} . C u (O H)_{2} (s) \to 2 C u O (s) + C O_{2} (g) ↑ + H_{2} O (l)$

Frequently Asked Questions-FAQ

Q1. What distinguishes copper oxide from cupric oxide?
Solution: Cuprous and cupric vary primarily because cuprous is a copper +1 cation, whereas cupric is a copper +2 cation. Copper and oxygen combine to generate stable molecules Cu₂O and CuO. CuO is black in colour, while Cu₂O is red in colour.

Q2. What causes copper to turn green?
Solution: Copper will be oxidised by the atmospheric oxygen to cupric oxide. In the presence of atmospheric moisture and carbon dioxide, copper oxide further reacts to form slowly, a blue-green coloured basic copper carbonate.

Q3. Is CuO, an insulator?
Solution: Cupric oxide as a mineral is a ceramic insulator. However, tin films of cupric oxide can be doped and act as an n-type semiconductor.

Q4. What type of oxide is copper oxide?
Answer: CuO or copper oxide, is a basic substance. It reacts with an acid to form cupric salt.