Question

Describe the removal of \(\mathrm{SO}_{2}\) by \(\mathrm{CaO}\) (to form \(\left.\mathrm{CaSO}_{3}\right)\) in terms of a Lewis acid-base reaction.

Short answer

\( \mathrm{SO}_2 \) is the Lewis acid and \( \mathrm{CaO} \) is the Lewis base, forming \( \mathrm{CaSO}_3 \).

Step-by-step solution

Identify the acid and base

In a Lewis acid-base reaction, a Lewis acid is an electron pair acceptor, while a Lewis base is an electron pair donor. In this reaction, \( \mathrm{SO}_2 \) acts as the acid because it can accept an electron pair, whereas \( \mathrm{CaO} \) acts as the base because it can donate an electron pair.

Describe the interaction

Sulfur dioxide (\( \mathrm{SO}_2 \)) accepts an electron pair from the oxygen in calcium oxide (\( \mathrm{CaO} \)), thus \( \mathrm{SO}_2 \), the Lewis acid, interacts with \( \mathrm{CaO} \), the Lewis base. This interaction leads to the formation of a new compound, calcium sulfite (\( \mathrm{CaSO}_3 \)).

Explain the product formation

Upon accepting the electron pair from \( \mathrm{CaO} \), \( \mathrm{SO}_2 \) transforms and binds with calcium to form calcium sulfite (\( \mathrm{CaSO}_3 \)). This product formation confirms the Lewis acid-base reaction.

Key concepts

Electron Pair Acceptor

Let's start by understanding the "electron pair acceptor" in a Lewis acid-base reaction. In this context, a Lewis acid is an electron pair acceptor because it thrives on receiving electrons from other substances.
In our exercise, sulfur dioxide (\( \mathrm{SO}_2 \)) takes on this role.
Now, you might ask why \( \mathrm{SO}_2 \) is considered an electron pair acceptor. The reason is that \( \mathrm{SO}_2 \) has a sulfur atom with incomplete octet characteristics that can accept an electron pair to stabilize itself.

• When \( \mathrm{SO}_2 \) encounters a substance capable of providing electron pairs, it accepts them through its sulfur atom.
• This acceptance of electron pairs is fundamental to forming stable compounds in chemical reactions.
• Remember, electron pair acceptors like \( \mathrm{SO}_2 \) are crucial in many reactions, driving the transformation of reactants into products.

By accepting an electron pair, \( \mathrm{SO}_2 \) initiates a reaction leading to the formation of new chemical compounds.

Electron Pair Donor

On the flip side of the Lewis acid-base reaction, we have the "electron pair donor." A Lewis base is defined as a substance that can donate an electron pair.
In this exercise, calcium oxide (\( \mathrm{CaO} \)) functions as the electron pair donor.
But why \( \mathrm{CaO} \) out of all compounds? Well, it has an oxygen atom capable of providing the electron pairs essential for bond formation.

• The oxygen in \( \mathrm{CaO} \) has lone pairs of electrons it is willing to share.
• This willingness to donate electrons allows \( \mathrm{CaO} \) to interact with electron pair acceptors such as \( \mathrm{SO}_2 \).
• The donation results in creating a new bond, which is a key step in forming compounds like calcium sulfite (\( \mathrm{CaSO}_3 \)).

Overall, the role of electron pair donors is almost like a handshake offer in chemical bonding, crucial to interactions and reactions.

Calcium Sulfite

Calcium sulfite (\( \mathrm{CaSO}_3 \)) is the end product of the reaction between sulfur dioxide (\( \mathrm{SO}_2 \)) and calcium oxide (\( \mathrm{CaO} \)).
This product formation is a perfect illustration of a Lewis acid-base reaction in action.
Calcium sulfite is an important compound that forms when \( \mathrm{SO}_2 \) accepts an electron pair from \( \mathrm{CaO} \).

• \( \mathrm{CaSO}_3 \) is produced in processes like desulfurization of flue gases, which helps reduce air pollution caused by \( \mathrm{SO}_2 \).
• It's important in industries where controlling and removing sulfur dioxide is essential for clean air regulations.
• The formation and stability of \( \mathrm{CaSO}_3 \) highlight the successful application of Lewis acid-base theory in practical chemical reactions and processes.

Understanding calcium sulfite formation can be a stepping stone in comprehending broader environmental chemistry applications.

Sulfur Dioxide Reaction

The reaction involving sulfur dioxide (\( \mathrm{SO}_2 \)) and calcium oxide (\( \mathrm{CaO} \)) is a classic example of a sulfur dioxide reaction playing out in chemical terms.
\( \mathrm{SO}_2 \) is prevalent in industrial emissions and, when uncontrolled, can contribute to environmental concerns like acid rain.

• The reaction with \( \mathrm{CaO} \) represents an effective method to mitigate \( \mathrm{SO}_2 \) emissions.
• Calcium oxide reacts with sulfur dioxide under specific conditions to produce calcium sulfite (\( \mathrm{CaSO}_3 \)), significantly reducing \( \mathrm{SO}_2 \) in the atmosphere.
• This reaction showcases how understanding chemical interactions can guide the development of methods to tackle environmental pollution.

Thus, the \( \mathrm{SO}_2 \) reaction in terms of a Lewis acid-base interaction provides a double benefit: advancing chemical knowledge and offering practical solutions for a cleaner environment.