Question

Chlorine is prepared industrially by heating hydrogen chloride gas with oxygen gas. Assuming the only products are water and chlorine gas, write a balanced chemical equation for the manufacture of chlorine.

Short answer

The balanced chemical equation is \[ 4\text{HCl} + \text{O}_2 \rightarrow 2\text{H}_2\text{O} + 2\text{Cl}_2 \]

Step-by-step solution

Identify Reactants and Products

The reactants in this reaction are hydrogen chloride gas (HCl) and oxygen gas (O2). The products of the reaction are water (H2O) and chlorine gas (Cl2).

Write the Unbalanced Equation

Start by writing down the unbalanced equation: \[ \text{HCl} + \text{O}_2 \rightarrow \text{H}_2\text{O} + \text{Cl}_2 \]

Balance Chlorine Atoms

To balance the chlorine atoms, note that there are two chlorine atoms in the chlorine gas molecule (Cl2) and one in the HCl molecule. Use a coefficient of 2 for HCl to balance the chlorine atoms: \[ 2\text{HCl} + \text{O}_2 \rightarrow \text{H}_2\text{O} + \text{Cl}_2 \]

Balance Hydrogen Atoms

Now balance the hydrogen atoms. Since there are 2 hydrogen atoms in HCl and 2 in H2O, there are already 2 H atoms on the reactant side and 2 on the product side, so they are balanced.

Balance Oxygen Atoms

With 1 molecule of O2 providing 2 oxygen atoms, and knowing that each water molecule contains 1 oxygen atom, you need two water molecules on the right side to balance the 2 oxygen atoms from the left side: \[ 4\text{HCl} + \text{O}_2 \rightarrow 2\text{H}_2\text{O} + 2\text{Cl}_2 \]

Verify Balanced Equation

Count the atoms for each element to ensure they are equal on both sides of the equation. There are 4 H, 4 Cl, and 2 O atoms on both sides of the equation, confirming the equation is balanced.

Key concepts

Reactants and Products

In any chemical reaction, reactants are the starting substances, while products are the substances formed as a result of the reaction. Reactants undergo chemical changes during the reaction. For the chlorine preparation, the reactants involved are hydrogen chloride gas (HCl) and oxygen gas (O\(_2\)). These substances are chemically transformed into products, which in this case are water (H\(_2\)O) and chlorine gas (Cl\(_2\)). Understanding this difference is crucial, as it sets the stage for balancing the chemical equation by aligning the reactant and product sides through stoichiometric coefficients. This helps ensure the same number of each type of atom is present on both sides of the equation, maintaining the law of conservation of mass.

Chlorine Preparation

Chlorine is widely used in various industrial applications, such as manufacturing and sanitization. The preparation of chlorine gas is done by a chemical reaction involving hydrogen chloride gas and oxygen gas. The reaction is influenced by several parameters:

• Temperature: Heating aids the reaction, providing the energy necessary to break and form bonds.
• Catalysts: Certain substances like copper chloride can speed up the reaction without being consumed.

In the process, hydrogen chloride reacts with oxygen to form water and liberates chlorine gas. The reaction is significant in industries because it provides a controlled method to obtain chlorine, minimizing impurities and maximizing yield.

Industrial Chemistry

Industrial chemistry plays a fundamental role in scaling up chemical reactions from the laboratory to factory production. This field focuses on optimizing chemical processes for efficiency and cost-effectiveness. In the industrial preparation of chlorine:

• Large-scale facilities are equipped to handle high temperatures and pressures, crucial for reacting HCl and O2 efficiently.
• Recycling reactant gases and managing by-products like water enhance sustainability.

Such practices ensure that chemical reactions yield the desired products in large quantities while minimizing waste. Industrial chemists work extensively on refining these processes to increase safety and environmental friendliness, reducing the emission of pollutants during production.

Chemical Reaction

A chemical reaction involves the transformation of one or more substances into new products. This process occurs through breaking and forming of chemical bonds. The reaction between hydrogen chloride and oxygen can be represented by a balanced chemical equation:\[ 4\text{HCl} + \text{O}_2 \rightarrow 2\text{H}_2\text{O} + 2\text{Cl}_2 \]Balancing equations ensures that atoms are conserved, reflecting the principle of conservation of mass. Each element must have the same number of atoms on both sides of the equation. The coefficients in front of the chemical formulas in the equation are adjusted to achieve this balance. Balancing equations is an essential skill in chemistry, as it allows the calculation of reactants needed and products formed in a reaction, pivotal for experimental and industrial purposes.