Copper Hydroxide

What is Copper Hydroxide?

Copper hydroxide is the resultant compound that is formed due to the addition of potassium or sodium hydroxide in a solution of copper salt. One of the distinguishing elements of copper hydroxide is its pale blue color. Mainly copper hydroxide can be found in the form of crystalline structure. Another common way of preparing copper hydroxide is by adding aqueous ammonia into cupric sulfate. Then the hydroxide is precipitated from the solution while adding the same amount of alkali. It is quite a commonly used compound in laboratories.

What is the Formula for Copper Hydroxide?

The formula of copper hydroxide is given by Cu(OH)2. Some of the most common names of copper hydroxide are cuprous hydroxide, cupric hydroxide and lastly copper(2+) hydroxide, which is actually its IUPAC name.

Overview

Structure of Copper Hydroxide

Cu(OH)2 has a square pyramidal structure. By using x-ray crystallography, the structure of copper hydroxide can be easily derived. The distance between Cu-O in the plane region is kept at 1.96 Å, whereas the axial region has a difference of 2.36 Å. As for the hydroxide ligands, they are either found in doubly bridging or triply bridging.

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Physical Properties of Copper Hydroxide

Chemical Properties of Copper Hydroxide

• Copper hydroxide forms copper sulfate and water when reacted with sulfuric acid. The chemical equation is given by:

Cu(OH)2 + H2SO4 → CuSO4 + 2 H2O

• Copper hydroxide forms copper nitrate and water when it reacts with nitric acid. The chemical equation is given by:

Cu(OH)2 + 2HNO3 → Cu(NO3)2 + 2H2O

• What happens when copper hydroxide is heated? It actually produces copper oxide, CuO, which is a black colored solid. The chemical equation is:

Cu(OH)2 (s) → CuO (s) + H2O (l)

• It is mildly amphoteric in nature.

• It can dissolve slightly in concentrated alkaline solutions.

Important Chemical Reactions

• We all know what is the chemical formula of copper hydroxide, but the same can also be found in the form of minerals. It is known as spertiniite. The green coating we can find on copper materials is due to the slow reaction with carbon dioxide in the air, which forms copper carbonate. The chemical reaction is given by:

2 Cu(OH)2 + CO2 → Cu2CO3(OH)2 + H2O

Copper Hydroxide Uses

Down below is a list of some of the most common applications on what is copper hydroxide used for:

• Copper hydroxide, when mixed with Schweizer’s Reagent (also known as ammonia solution), has the capability to actually get dissolved in cellulose

• The intriguing property of copper hydroxide is actually used in the production of rayon, which is a cellulose-based fiber.

• It is heavily used in aquaculture in order to destroy external microbes in fishes, which includes flukes, marine velvet as well as brook, without providing any harm to the fish. Other compounds of copper are also effective, but one of their biggest drawbacks is the higher mortality in fishes.

• Copper hydroxide used in agriculture is also effective, as it can readily work as an excellent fungicide.

• Copper hydroxide packed with latex paint is most effective in keeping the root growth in check for potted plants.

• This actually results in a dense and healthier root without compromising the space that is required to grow them.

• Lastly, copper hydroxide is also used as a ceramic colourant.

Solved Questions

Example 1

Whenever copper hydroxide reacts with an excess amount of ammonium sulphate and ammonium hydroxide, it turns into a deep blue solution. So, what is the formula of the solution?

a)     [Cu(NH3​)4​]SO4

b)     [Cu(NH4)4​]SO4

c)     [Cu(NH4​)3​]SO4

d)     [Cu(NH3​)3​]SO3

Solution:

The reaction between copper hydroxide along with ammonium sulphate and ammonium hydroxide is given by:

CuCl2 ​+ (NH4​)2​SO4​ + 2NH4​OH ⟶ 4H2​O + [Cu(NH3​)4​]SO4​

So, the right answer is:

a) [Cu(NH3​)4​]SO4, which is actually a characteristic property of Cu2+

Example 2

Among the following compounds, which of the following is more likely to be a soluble base?

a) Cu(OH)2

b) Ga(OH)3

c) Ca(OH)2

d) Zn(OH)2

e) Zr(OH)3

Solution:

The answer is:

c) Ca(OH)2