Question

What is produced when cuprous oxide reacts with HCl? (a) \(\mathrm{CuCl}\) (b) \(\mathrm{CuO}\) (c) \(\mathrm{HCuCl}_{2}\) (d) \(\mathrm{CuCl}_{2}\)

Short answer

CuCl and water are produced when cuprous oxide reacts with HCl. Correct option is (a) \\( \mathrm{CuCl} \\).

Step-by-step solution

Write the Chemical Equation

Cuprous oxide, or Cu2O, reacts with hydrochloric acid, HCl. The reaction can be described by the chemical equation Cu2O + HCl -> products. We need to identify the products of this reaction.

Determine the Ion Exchange

Cuprous oxide contains Cu+ ions. When reacting with HCl, the Cu+ ions react with Cl- ions from HCl. Since each Cu+ ion requires one Cl- to form CuCl, the reaction involves combining these ions.

Balance the Chemical Equation

Based on the ion exchange, the balanced equation is: \[ \mathrm{Cu_2O + 2 HCl \rightarrow 2 CuCl + H_2O} \]. This shows that each oxygen atom binds with two protons (H+) to form one molecule of water (H2O), confirming that CuCl is produced along with water.

Verify the Product

After balancing, the product formed is CuCl. Options confirm that \( \mathrm{CuCl} \) is choice (a) in the provided options. Hence, we have correctly identified the product.

Key concepts

Cuprous Oxide

Cuprous oxide, chemically represented as \( \mathrm{Cu_2O} \), is a red or reddish-brown mineral carrying copper in a +1 oxidation state. It is an important compound in the family of copper oxides and is often used in the manufacturing of ceramics and antifouling paints. Cuprous oxide is unique due to its lower oxidation state compared to cupric oxide \( \mathrm{CuO} \), which contains copper in a +2 state.
Cuprous oxide usually forms as a result of the oxidation of copper metal. Its structure is cubic, and it often forms isometric crystals that contribute to its shiny appearance. In addition, this oxide is commercially produced through electrolytic or pyrometallurgical processes.

Hydrochloric Acid

Hydrochloric acid, \( \mathrm{HCl} \), is a colorless, pungent-smelling acidic solution formed by dissolving hydrogen chloride in water. It is a strong acid commonly used in industrial, laboratory, and production processes.
In chemistry, \( \mathrm{HCl} \) is known for its aggressive nature, readily donating protons \( \mathrm{H^+} \) to bases in acid-base reactions. This capacity to dissociate easily into \( \mathrm{H^+} \) and \( \mathrm{Cl^-} \) ions in solution makes it ideal for titration methods in laboratories to determine the concentration of unknown bases. Its reactivity is precisely why \( \mathrm{HCl} \) is crucial in these reactions, allowing for efficient ion exchanges.

Ion Exchange

Ion exchange is a process where ions are swapped between a solution and a solid, or between two solutions, leading to a chemical change. In the reaction between cuprous oxide and hydrochloric acid, ion exchange is crucial.
This chemical exchange occurs when \( \mathrm{Cu^{+}} \) ions from \( \mathrm{Cu_2O} \) react with \( \mathrm{Cl^{-}} \) ions from \( \mathrm{HCl} \). This specific interaction results in the formation of \( \mathrm{CuCl} \), illustrating a compelling example of ion exchange.
Ion exchange processes are not only limited to laboratory reactions; they are widely used in water purification, separation of heavy metals, and improving soil nutrient composition.

Balancing Chemical Equations

Balancing chemical equations is a fundamental task in chemistry ensuring that the number of atoms for each element is equal on both sides of the equation. This represents the concept of conservation of mass, where the number of atoms in the reactants matches that in the products.
In the reaction of cuprous oxide and hydrochloric acid, we wrote the equation as
\[ \mathrm{Cu_2O + 2 HCl \rightarrow 2 CuCl + H_2O} \]
Here, we balanced the equation by ensuring that the number of each type of atom, such as copper, hydrogen, oxygen, and chlorine, was the same on both sides of the equation. Balancing this equation ensures the law of conservation of mass is obeyed, enabling accurate predictions of product yields in practical chemical reactions.

• First, balance metals (e.g. Cu).
• Next, balance nonmetals (e.g. Cl).
• Finally, balance hydrogen and oxygen atoms.

These steps help chemists and students ensure precision and consistency in describing chemical reactions.