Question

What is the principle involved in the preparation of \(\mathrm{FeCl}_{3} ?\)

Short answer

Answer: The principle involved in the preparation of ferric chloride (FeCl₃) is a redox reaction between iron (Fe) and chlorine (Cl), wherein iron undergoes oxidation by losing electrons and chlorine undergoes reduction by gaining electrons, resulting in the formation of an ionic compound, ferric chloride (FeCl₃).

Step-by-step solution

Identify the reactants and products

In the preparation of \(\mathrm{FeCl}_{3}\) (ferric chloride), the reactant is iron (Fe) and chlorine (Cl) and the product is ferric chloride (\(\mathrm{FeCl}_{3}\)).

Write the balanced chemical equation for the preparation of \(\mathrm{FeCl}_{3}\)

The balanced chemical equation for the preparation of ferric chloride is: $$ 2\mathrm{Fe} + 3\mathrm{Cl}_{2} \rightarrow 2\mathrm{FeCl}_{3} $$

Principle involved in the preparation of \(\mathrm{FeCl}_{3}\)

The principle involved in the preparation of \(\mathrm{FeCl}_{3}\) is the combination of iron (Fe) with chlorine (Cl) through a redox reaction, in which iron (Fe) loses electrons and chlorine (Cl) gains electrons. In this reaction, iron undergoes oxidation, and chlorine undergoes reduction. The product is ferric chloride (\(\mathrm{FeCl}_{3}\)), an ionic compound formed due to the transfer of electrons between the metal (iron) and the non-metal (chlorine).

Redox half-reactions

The redox half-reactions for the preparation of \(\mathrm{FeCl}_{3}\) can be written as follows: Oxidation half-reaction (iron loses 3 electrons): $$ \mathrm{Fe} \rightarrow \mathrm{Fe}^{3+} + 3e^{-} $$ Reduction half-reaction (chlorine gains 1 electron): $$ \mathrm{Cl}_{2} + 2e^{-} \rightarrow 2\mathrm{Cl}^{-} $$

Summary

The principle involved in the preparation of \(\mathrm{FeCl}_{3}\) is a redox reaction, wherein iron (Fe) combines with chlorine (Cl). Iron undergoes oxidation by losing electrons, and chlorine undergoes reduction by gaining electrons. The resulting product is an ionic compound, ferric chloride (\(\mathrm{FeCl}_{3}\)).

Key concepts

Redox Reaction

A redox reaction, short for reduction-oxidation reaction, is a chemical reaction where one substance loses electrons (oxidation) and another gains electrons (reduction). These two processes always occur together in a redox reaction. In the case of ferric chloride preparation, iron (Fe) atoms lose electrons, which is the oxidation part, while chlorine (Cl₂) molecules gain electrons, which is the reduction part. As a result, Fe atoms become positively charged ions (Fe³⁺) and Cl molecules split into negatively charged ions (Cl^-). The transfer of electrons changes the oxidation states of the atoms, leading to the formation of new substances.

Oxidation State Changes

• Iron (Fe) starts with an oxidation state of 0 and becomes Fe³⁺ (oxidation state of +3)
• Chlorine (Cl₂) starts with an oxidation state of 0 and becomes Cl^- (oxidation state of -1)

A balanced equation ensures that the number of electrons lost in the oxidation half of the reaction equals the number of electrons gained in the reduction half.

Balanced Chemical Equation

A balanced chemical equation is crucial in chemistry to show that mass and charge are conserved during a reaction. The equation for the formation of ferric chloride is balanced by ensuring that the number of atoms for each element is the same on both the reactant and product sides. This balance is achieved by adjusting the coefficients (the numbers in front of the chemical formulas).

Ensuring Balance

• There are 2 atoms of iron on both sides of the equation: 2Fe and 2FeCl₃.
• There are also 6 atoms of chlorine on both sides: 3Cl₂ and 6Cl^- in 2FeCl₃.

Balancing a chemical equation ensures that the law of conservation of mass is upheld, indicating matter cannot be created or destroyed in a chemical reaction.

Oxidation and Reduction

Oxidation and reduction describe the movement of electrons between atoms, signaling a fundamental change in the participating substances. Oxidation involves the loss of electrons, while reduction involves the gain of electrons. In general terms, the substance that loses electrons is called the reducing agent, and the substance that gains them is called the oxidizing agent.

Examples in Ferric Chloride Formation

• Iron (Fe) loses three electrons and is oxidized to Fe³⁺, acting as the reducing agent.
• Chlorine (Cl₂) molecule gains two electrons to form two Cl^- ions, acting as the oxidizing agent.

Understanding oxidation and reduction is essential in the study of redox reactions and helps comprehend the changes in chemical properties as atoms transform into ions, leading to the formation of ionic compounds.

Ionic Compound Formation

Ionic compounds form when metals react with non-metals, transferring electrons from the metal to the non-metal. This transfer leads to the creation of ions, charged particles, which are then held together by electrostatic forces known as ionic bonds. In creating ferric chloride, positively charged iron ions (Fe³⁺) and negatively charged chloride ions (Cl^-) combine to form an ionic compound, FeCl₃.

Characteristics of Ionic Bonds

• Ionic bonds are strong and result in the formation of crystalline solids at room temperature.
• These compounds typically have high melting and boiling points because of the strong attraction between the positively and negatively charged ions.
• In an aqueous solution, ionic compounds often dissociate into their individual ions, which is why they are good conductors of electricity in this state.

The formation of FeCl₃ exemplifies ionic bonding and underscores the significance of electron transfer in producing stable ionic substances.