What Happens when Copper Sulfate Reacts with Concentrated Sulphuric Acid?

Read this detailed article explaining the reaction of copper and sulphuric acid in concentrated form and copper sulfate with the same acid too.  

Introduction:

Copper (Cu) belongs to the Transition metal, Group 11, and in its metallic form, it has a distinct reddish-orange color with a bright metallic luster. This metal is known for its high ductility and is readily used to be drawn in thin wires. That is why it is found in most of the conducting wires in current times.

Copper sulfate (CuSO₄) usually appears white when in anhydrous form and when exposed to moisture, it takes a blue crystalline form. Sulphuric acid (H₂SO₄) is a commonly available acid that is a strong oxidizing agent. It is also a very strong dehydrating acid meaning that it can remove water molecules from the molecules of the substances it may be reacting.

Reaction of Copper and Sulphuric acid

Their reaction is a classic example of a single displacement reaction and metal acid reaction.  Their reaction the two can have slightly different products which depend on the concentration of the sulphuric acid. If the acid used is dilute, then their reaction can be stated as:

Cu + H₂SO₄ → CuSO₄ + H₂

The result is Copper sulfate along with hydrogen gas being evaporated from the resultant solution. The water present in the diluted sulphuric acid causes the production of hydrogen gas during the reaction. It is also worth mentioning that too much diluted sulphuric acid won’t react with copper at all as copper is well below hydrogen in the reactivity series of metals that won’t be able to easily remove hydrogen from sulphuric acid. Even if the concentration is good enough, heat may be required to initiate their reaction. If the H₂SO₄ is concentrated then the (redox) reaction can be stated as:

Cu + 2H₂SO₄ → CuSO₄+ SO₂ + 2H₂O

Note that now when copper in sulfuric acid reacts in higher concentration with its counterpart, SO₂ gas is emitted. This happens due to the strong oxidizing property of the concentrated sulphuric acid. Moreover, the precipitate formed during the reaction is CuSO₄ which may settle down as a solid. Both copper and Sulphuric acid vigorously react with each other along with the emission of sulfur dioxide gas due to which, proper PPE and care are advised.  

Reaction of Copper Sulphate and Sulphuric acid

Their reaction may result in two different products which may depend on the concentration of sulphuric acid, stoichiometry, and reaction conditions. The first condition will be the production of an intermediate compound, Copper (II) Hydrogen Sulfate (Cu(HSO4)2) along with water. This reaction can be stated as:

CuSO₄ + H₂SO₄ → Cu(HSO₄)₂ + H₂O

If the acid concentration is high, their reaction will also produce sulfur dioxide gas which can be observed as a colorless but pungent odor gas:

CuSO₄ + 2H₂SO₄ → CuSO₄ + SO₂ + 2H₂O

Note in that both cases, sulphuric acid takes away water and is released as a byproduct at the end of the reaction. The result is anhydrous copper sulfate which has lost all its water.

Applications of CuSO₄ and H₂SO₄ Solution:

The reaction of copper with sulphuric acid and its sulfate has several significant applications in the industry. The first one is in the electroplating process where copper is used along with a sulphuric acid solution which provides the necessary ions for the electroplating process. In water treatment, both copper and sulphuric acid are used to neutralize various alkaline wastes in the water and also help to precipitate heavy metals in the water systems. The solution of copper sulfate and sulphuric acid is also used in various herbicides and fungicides. Both are also used as laboratory reagents and a source of copper ions for various other reactions.

Conclusion:

The reaction of both copper and Sulphuric acid and copper sulfate and sulphuric depends on the concentration levels of the acid. In lower concentrations, the metal sulfate won’t react at all but in higher concentrations will yield sulfur dioxide SO₂ gas. Both find several applications in the industry and as well as in academic laboratories.