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Important Compounds of Copper- Definition, Important Compounds of Copper, Preparations, Properties, Uses, Practice Problems, FAQs

Important Compounds of Copper- Definition, Important Compounds of Copper, Preparations, Properties, Uses, Practice Problems, FAQs

Have you seen the inner wire of electrical appliances? Whenever an electrician visits your house, he must sharpen the inner wire of the machine or electrical wiring. Have you seen shining thin wire inside the plastic-coated substance? Have you asked your teacher about this? What kind of materials are used in electrical wiring or in electrical appliances? You must have studied in books that silver is the best conductor of electricity, right? Although silver is a superior electrical conductor than copper, it is significantly more expensive and therefore not utilised for wiring. Yes, the wire which we are using in our house for electrical wirings are generally made up of copper. Copper is also 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 easily than a stone between 7,000 and 10,000 years ago, a discovery that would impact humanity forever. The first step out of the Stone Age and into the Ages of Metals, this age would be this meeting of humans with metals. Copper and bronze were often used for coinage. During the historic period, economic activity and increased international trade flourished with the help of copper coins or alloys made up of copper.
Let’s study some important compounds derived from copper and see how beneficial they are. So come and let’s begin!

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Table of content:

  • What is copper?
  • Some Important compounds of copper
  • Cuprous Chloride
  • Cupric Chloride
  • Cupric Oxide
  • Practice Problems
  • Frequently asked questions-FAQs

What is copper?

Copper has been used by humans from prehistoric times. The symbol 'Cu'' short for the Latin term 'cuprum,' represents the 29th element in the periodic table. Copper has a density of 8.96 gcm-3. It has a relative atomic mass equal to 63.546 u. Copper belongs to the group of transition metals and specifically from d-block. Copper is found in only 0.0001% of the earth's crust. However, its deposits are concentrated. Copper can be found in the following forms in nature.

1. Native state: Copper is abundant in metallic form in Lake Superior in the United States, as well as in the Ural Mountains in Russia and Sweden.
2. Combined state: Sulphides, oxides, and basic carbonates are the most common copper ores which are found in combined states.

Some Important compounds of copper:

There are many compounds of copper which are extracted in a variety of ways, Let’s discuss a few important compounds of copper.

  • Cuprous Chloride
  • Cupric Chloride
  • Cupric Oxide
  • Copper Sulphate (Blue Vitriol)

We will study Cuprous Chloride, Cupric Chloride, and Cupric Oxide in detail.

Cuprous Chloride (Cu2Cl2):

Copper is divided into two types of compounds. One is cuprous compounds and another one is cupric compounds. Cuprous chloride is the most important compound in cuprous class. Cuprous chemicals are usually water-insoluble. Because the soluble compounds are disproportionate to Cu2+ and Cu , they are unstable in aqueous solutions.

Preparation of cuprous chloride:

  • By heating surplus copper in strong hydrochloric acid with a little amount of potassium chlorate(For oxidation)
    Cu(s)+2HCl(aq)+[O]CuCl2(s)+H2O(aq)

CuCl2(s)+Cu(s)Cu2Cl2(s)

  • In the presence of hydrochloric acid, boiling copper sulphate solution with excess copper.


CuSO4(s)+2HCl(aq)CuCl2(s)+H2SO4(aq)

CuCl2(s)+Cu(s)Cu2Cl2(s)

  • Cupric chloride is heated using zinc or sulphur dioxide to obtain cuprous chloride.


2CuCl2(s)+Zn(s)Cu2Cl2(s)+ZnCl2(s)
 

2CuCl2(s)+2H2O(aq)+SO2(g)Cu2Cl2(s)+2HCl(aq)+H2SO4(aq)

  • SO2 is passed through a solution of copper sulphate and sodium chloride to obtain cuprous chloride.

    2CuSO4(s)+2NaCl(s)+2H2O(aq)+SO2(g)Cu2Cl2(s)+Na2SO4(s)+2H2SO4(aq)

Properties and Reactions of cuprous chloride:

  • It's a solid white colour. It is soluble in excess hydrochloric acid but not in water or on dilution, the solution produces a white precipitate..

    Cu2Cl2(s)+4HCl(aq)2H2CuCl3(s)
     

Cu2Cl2(s)+6HCl(aq)2H3CuCl4(s)

  • Due to oxidation, it progressively turns green when exposed to air.

    2Cu2Cl2(s)+2H2O(aq)+O2(g)2[CuCl2.Cu(OH)2](solid basic cupric chloride)
  • Cuprous chloride solution in HCl is oxidised to cupric chloride by air or some oxidising agents.

    Cu2Cl2(s)+2HCl(aq)+12O2(g)2CuCl2(s)+H2O(aq)
     
  • Cuprous chloride dissolves in HCl and absorbs carbon monoxide, forming an addition compound.

    Cu2Cl2(s)+2CO(g)2CuCl.CO(g)

    When heated, the addition compound decomposes, releasing carbon monoxide. The process is used to remove carbon monoxide from the atmosphere.
  • Due to the production of the complex Cu(NH3)2Cl, it dissolves in aqueous ammonia and forms a colourless solution.
  • The ammoniacal cuprous chloride solution absorbs acetylene and forms a brilliant red cuprous acetylide precipitate,Cu2C2.

    2Cu(NH3)2Cl(s)+C2H2(g)Cu2C2(s)+2NH3(g)+2NH4Cl(s)

    The acetylide can be treated with strong HCl to regenerate acetylene. As a result, the reaction is employed in the purification and separation of acetylene.

    Cu2Cl2(s)+2HCl(aq)C2H2(g)+Cu2Cl2(s)

Uses of cuprous chloride:

  • Acetylene is absorbed using an ammonical solution of cuprous chloride.
  • Carbon monoxide is absorbed using a cuprous chloride HCl solution.
  • It can also be used to absorb ammonia gas.
  • It is utilised as a catalyst in Deacon's chlorine gas manufacturing process.

Cupric Chloride (CuCl2):

Cupric chloride is a chemical compound having the formula CuCl2. The anhydrous form is yellowish brown, but when it absorbs moisture, it turns blue-green and form dihydrate compound (CuCl2.2H2O)

Preparation of Cupric chloride:

  • In conc.HCl, the metal copper, cupric oxide, cupric hydroxide, or copper carbonate is dissolved. On crystallisation, the resultant solution yields green crystals of hydrated cupric chloride.

    2Cu(s)+4HCl(aq)+O2(g)2CuCl2(s)+2H2O(aq)

    CuO(s)+2HCl(aq)CuCl2(s)+H2O(aq)

    CuCO3.Cu(OH)2(s)+4HCl(aq)2CuCl2(s)+3H2O(g)+CO2(g)
     
  • When copper metal is heated in excess of chlorine gas or hydrated cupric chloride is heated in HCl gas at 150°C, anhydrous cupric chloride forms as a dark brown mass.

    Cu(s)+Cl2(g)CuCl2(s)

Properties of and reactions Cupric chloride:

  • It is a deliquescent chemical that dissolves easily in water. The concentrated solution is green, but the dilute solution is blue. When Conc. HCl is introduced, it turns yellow. When both are present, the blue colour is due to complex cation [Cu(H2O)4]2+ and the yellow colour is due to complex anion [CuCl4]2-.
  • Because of hydrolysis of cupric chloride, the aqueous solution is acidic in nature.
    While On strong heating, the hydrated salt produces CuO, Cu2Cl2,HCl and Cl2.

    3CuCl2.2H2O(s)CuO(s)+Cu2Cl2(s)+2HCl(aq)+Cl2(g)+5H2O(aq)
     
  • Copper turnings, SO2 gas, hydrogen (nascent-obtained via the action of HCl on Zn), or SnCl2 are all easily reduced to Cu2Cl2.

    CuC2(s)+Cu(s)Cu2Cl2(s)

    2CuCl2(s)+SO2(g)Cu2Cl2(s)+2HCl(aq)+H2SO4(aq)

    2CuCl2(s)+[H]Cu2Cl2(s)+2HCl(aq)

    2CuCl2(s)+SnCl2(s)Cu2Cl2(s)+SnCl4(s)
     
  • When NaOH is added, a pale blue precipitate of basic cupric chloride i.e; CuCl2.3Cu(OH)2, is formed.

    CuCl2(s)+2NaOH(s)Cu(OH)2(s)+2NaCl(s)

    CuCl2(s)+3Cu(OH)2(s)CuCl2.3Cu(OH)2(s)

Uses of cupric chloride:

  • In Deacon's method, it acts as a catalyst.
  • It's also utilised in medicine and in the production of organic dyestuffs as an oxygen carrier.

Cupric Oxide (CuO):

Cupric oxide is a copper black 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℃.

    Cu2O(s)+12O2(g)2CuO(s)
     

2Cu(s)+O2(g)2CuO(s)

  • Cupric hydroxide is heated to get Cupric oxide.

    Cu(OH)2(s)CuO(s)+H2O(aq)
     
  • Copper nitrate is heated to produce Cupric oxide.

    2Cu(NO3)2(s)2CuO(s)+4NO2(g) ↑+O2(g) ↑
     
  • It's made on a commercial basis by heating malachite, which is present in nature.

    CuCO3.Cu(OH)2(s)2CuO(s)+CO2(g) ↑+H2O(aq)

Properties and reactions of cupric oxide:

  • It is a black powder that is stable till mild heating.
  • The oxide is water-insoluble, but it dissolves in acids and forms salts.

    CuO(s)+2HCl(aq)CuCl2(s)+H2O(aq)

    CuO(s)+H2SO4(aq)Cu2SO4(s)+H2O(aq)

    CuO(s)+2HNO3(aq)Cu(NO3)2+H2O(aq)
     
  • It is transformed to cuprous oxide with the release of oxygen when heated to 1100-1200°C.

    4CuO(s)2Cu2O(s)+O2(g) ↑
     
  • Reducing agents such as hydrogen, carbon, and carbon monoxide convert Cupric oxide to metallic copper.

    CuO(s)+H2(g)Cu(s)+H2O(aq)

    CuO(s)+C(s)Cu(s)+CO(g) ↑

    CuO(s)+CO(g)Cu(s)+CO2(g) ↑
     

Uses of cupric oxide:

  • It is used to give glazes and glass a green to blue colour.
  • It is utilised for carbon estimation and detection in organic analysis.
  • It is also used to remove sulphur from petroleum.

Cuprous Oxide:

The inorganic compound Cu2O, also known as copper(I) oxide or cuprous oxide, is an inorganic compound with the formula Cu2O. It is one of two major copper oxides, the other being copper(II)oxide, also known as cupric oxide (CuO).

Preparation of cuprous oxide:

  • Copper(I) oxide can be made in a variety of ways. It is produced most simply by the oxidation of copper metal.

    4Cu(s)+O2(g)2Cu2O(s)

Properties and reactions of cuprous oxide:

  • Cuprous oxide generally boils around 1800℃ and melts around 1232℃
  • Density of cuprous oxide comes out to be 6 g cm-3.
  • In the presence of oxygen, copper(I) oxide interacts with water to generate copper(II) hydroxide. The chemical formula is shown below.

    2Cu2O(s)+4H2O(aq)+O2(g)4Cu(OH)2(s)
     
  • Copper(I) chloride and water are formed when copper(I) oxide interacts with hydrogen chloride. The chemical formula is shown below.

    Cu2O(s)+2HCl(g)2CuCl(s)+H2O(aq)
     
  • It's a covalent substance. The cubic structure of copper(I) oxide crystallises.
  • When heated, hydrogen easily reduces it. It disproportions in acid solutions, creating copper(II) ions and copper(III) ions.
  • Cupric oxide is transformed into cuprous oxide when it is gently heated with metallic copper.

Uses of cuprous oxide:

  • It is an efficient corrosion control agent used in antifouling paints for boat and ship bottoms.
  • Glass and porcelain paints include this ingredient.
  • It was used to produce photocells for light metres and fabricate rectifiers as a p-type semiconductor material.
  • It's used as a fungicide as well as a seed dressing.

Practice Problems:


Q1. Cuprous chloride generates a black cuprous sulphide precipitate with_______________.
a. H2SO4
b. Cu2SO4
c.H2S
d. PbS
Answer: C
Cuprous chloride reacts with H2S to generate a dark black cuprous sulphide precipitate.

Cu2Cl2(s)+H2S(g)Cu2S(s)+2HCl(aq)

Q2. _______________ is the oxide ore of copper.
a. Azurite
b. Cuprite
c. Chalcopyrites
d. Bornite,
Answer: B
Cuprite (red), Cu2O is the oxide ore of copper. Azurite (Cu3(OH)2(CO3)2, is the carbonate ore of copper whereas Chalcopyrites (CuFeS2) and Bornite (Cu5FeS4) are sulphide ore of copper.

Q 3.German silver along with copper is the alloy of ____________.
a.Zn and Ni
b. Zn and Al
c. Ni and Al
d. Al and Fe
Answer: A
German silver along with copper is the alloy of Zn and Ni. Compositions of copper is 56%, Zn is 24% and Ni is 20%

Q4.CuCl2 on dissolving in ammonium hydroxide gives a ___________ solution.
a. red
b. deep blue
c. light green
d. pale yellow
Answer: B
CuCl2 forms a deep blue solution when it dissolves in ammonium hydroxide. Deep blue tetrammine cupric chloride crystals are formed by evaporating this solution.

CuCl2(s)+4NH4OH(l)Cu(NH3)4Cl2.H2O(s)+3H2O(aq)

Frequently asked questions-FAQ

Q1. From where we can get copper deposits in India?
Answer: Copper is found primarily in Jharkhand's Singhbhum district, Matigara, and Dharwar.The Khetri copper belt in Rajasthan, the Singhbhum copper belt in Jharkhand, and the Malanjkhand copper belt in Madhya Pradesh are the biggest copper mines.

Q2.What type of coating is done on the copper wire which is used in electrical wiring?
Answer: Wire enamels are varnishes that are applied to the surface of copper and cured to produce an electrically insulating film with mechanical strength, thermal resistance, and chemical resistance.

Q3.Is copper used by the human body?
Answer: Copper is an essential mineral for good health. Copper is used by the body for a variety of purposes, including energy production, connective tissue, and blood vessel formation. Copper also activates genes and aids in the maintenance of the brain and immunological systems.

Q4. Due to the excess amount of copper, humans suffer from which disease?
Answer: Wilson disease is a genetic condition in which the body accumulates excessive levels of copper, mainly in the liver, brain, and eyes. Wilson's illness is most commonly diagnosed in children between the ages of 5 and 35, but it can also affect younger and older persons.

Related topics

Iron

Potassium Permanganate

Inner transition elements

Water

Hydrogen

Important compounds of copper

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