Problem 99 - Chemistry: An Atoms-Focused Approach

Question

The water-soluble gas \(\mathrm{ClO}_{2}\) is known as an oxidative biocide. It destroys bacteria by oxidizing their cell walls and viruses by attacking their viral envelopes. \(\mathrm{ClO}_{2}\) may be prepared for use as a decontaminating agent from several different starting materials in slightly acidic solutions. Complete and balance the following chemical reactions for the synthesis of \(\mathrm{ClO}_{2}\) a. \(\mathrm{ClO}_{3}^{-}(a q)+\mathrm{SO}_{2}(g) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{SO}_{4}^{2-}(a q)\) b. \(\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}^{-}(a q) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{Cl}_{2}(g)\) c. \(\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}_{2}(g) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{O}_{2}(g)\)

Step-by-Step Solution

Answer

a) ClO3^-(aq) + SO2(g) → ClO2(g) + SO4^2-(aq) b) ClO3^-(aq) + Cl^-(aq) → ClO2(g) + Cl2(g) c) ClO3^-(aq) + Cl2(g) → ClO2(g) + O2(g) Answer: a) 2ClO3^-(aq) + SO2(g) → 2ClO2(g) + SO4^2-(aq) b) 2ClO3^-(aq) + Cl^-(aq) → 2ClO2(g) + Cl2(g) c) 2ClO3^-(aq) + Cl2(g) → 2ClO2(g) + O2(g)

Step 1: Balance Reaction a.

First, we will balance the given chemical reaction a: \(\mathrm{ClO}_{3}^{-}(a q)+\mathrm{SO}_{2}(g) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{SO}_{4}^{2-}(a q)\) To balance this reaction, we need to find coefficients that make the number of atoms of each element equal on both sides of the reaction. We can start balancing by adjusting the oxygen atoms. There are 2 O atoms in SO2 and 4 O atoms in SO4^2-. Since there are 3 O atoms in ClO3-, we can multiply ClO3- by 2 to balance the oxygen atoms in the reaction: \(2\mathrm{ClO}_{3}^{-}(a q)+\mathrm{SO}_{2}(g) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{SO}_{4}^{2-}(a q)\) Now, we have a total of 6 O atoms on both sides of the reaction. Next, let's balance the Cl atoms. We have 2 Cl atoms on the left side and only 1 Cl atom in ClO2. To balance the chlorine atoms, we can add a coefficient of 2 to ClO2. \(2\mathrm{ClO}_{3}^{-}(a q)+\mathrm{SO}_{2}(g) \rightarrow 2\mathrm{ClO}_{2}(g)+\mathrm{SO}_{4}^{2-}(a q)\) Finally, the S atoms are already balanced, with one S atom in SO2 and one in SO4^2-. Therefore, the balanced equation for reaction a is: \(2\mathrm{ClO}_{3}^{-}(a q)+\mathrm{SO}_{2}(g) \rightarrow 2\mathrm{ClO}_{2}(g)+\mathrm{SO}_{4}^{2-}(a q)\)

Step 2: Balance Reaction b.

Now, we need to balance the given chemical reaction b: \(\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}^{-}(a q) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{Cl}_{2}(g)\) To balance the oxygen atoms, we can see that they are already balanced with 3 O atoms in ClO3- and 2 O atoms in ClO2. Next, let's look at the Cl atoms. One Cl atom is in ClO3- and one in Cl-, while there are two Cl atoms in Cl2. We can multiply ClO3- by 2 to balance the chlorine atoms: \(2\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}^{-}(a q) \rightarrow 2\mathrm{ClO}_{2}(g)+\mathrm{Cl}_{2}(g)\) Finally, the balanced equation for reaction b is: \(2\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}^{-}(a q) \rightarrow 2\mathrm{ClO}_{2}(g)+\mathrm{Cl}_{2}(g)\)

Step 3: Balance Reaction c.

Finally, we need to balance the given chemical reaction c: \(\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}_{2}(g) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{O}_{2}(g)\) First, let's balance the oxygen atoms. Since there are 3 O atoms in ClO3- and 2 O atoms in O2, we can multiply ClO3- by 2: \(2\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}_{2}(g) \rightarrow \mathrm{ClO}_{2}(g)+\mathrm{O}_{2}(g)\) Now, we have 6 O atoms on both sides of the reaction. Finally, let's balance the Cl atoms. There are 2 Cl atoms in ClO3- and 2 Cl atoms in Cl2, and only 1 Cl atom in ClO2. To balance the chlorine atoms, we can add a coefficient of 2 to ClO2: \(2\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}_{2}(g) \rightarrow 2\mathrm{ClO}_{2}(g)+\mathrm{O}_{2}(g)\) The balanced equation for reaction c is: \(2\mathrm{ClO}_{3}^{-}(a q)+\mathrm{Cl}_{2}(g) \rightarrow 2\mathrm{ClO}_{2}(g)+\mathrm{O}_{2}(g)\)

Key Concepts

Oxidative Biocide

Chlorine dioxide \((\mathrm{ClO}_{2})\) is an effective oxidative biocide known for its ability to eliminate harmful microorganisms. This potent chemical compound works by disrupting the cellular structure of bacteria through oxidation. In oxidation, \(\mathrm{ClO}_{2}\) effectively breaks down the bacterial cell walls, causing cell death, which makes it an ideal disinfectant. This makes \(\mathrm{ClO}_{2}\) critical in various industries for sanitization purposes. Additionally, \(\mathrm{ClO}_{2}\) targets viruses by attacking their envelopes, thus rendering them inactive.

• Effective against a wide range of microorganisms, including bacteria and viruses.
• Highly used in water treatment facilities and the food industry.
• Ensures a broad-spectrum approach to microbial safety.

By understanding how \(\mathrm{ClO}_{2}\) functions as an oxidative biocide, one can see its importance in maintaining hygienic environments, especially where human health is a concern.

Synthesis of ClO2

The synthesis of chlorine dioxide \((\mathrm{ClO}_{2})\) involves various chemical reactions, which can be balanced through different methodologies. In typical chemical equations, elements appear as reactants on one side and products on the other. The goal in synthesis is to produce \(\mathrm{ClO}_{2}\) efficiently.
To balance the equations:

• Identify the number of atoms for each element in both reactants and products.
• Use coefficients to ensure the number of each type of atom is equal on both sides.

For example, in the reaction between chlorate \((\mathrm{ClO}_{3}^{-})\) and sulfur dioxide \((\mathrm{SO}_{2})\), the oxygen atoms get balanced first, followed by chlorine and sulfur.As such, understanding the principles of balancing chemical equations helps ensure the correct synthesis of \(\mathrm{ClO}_{2}\), which is crucial for its intended applications.

Acidic Solutions

Acidic solutions play a vital role in the synthesis of chemical compounds such as chlorine dioxide \((\mathrm{ClO}_{2})\). An acidic environment helps in smoothing out reactions, ensuring the desired outcomes are achievable. It involves more hydrogen ions \((\mathrm{H}^{+})\), which influences the overall reaction process.
Some characteristics of acidic solutions include:

• pH less than 7.
• Presence of excess hydrogen ions \((\mathrm{H}^{+})\).
• Ability to act as electrolytes conducting electricity.

In specific chemical reactions, the role of acidity helps to drive the reaction forward by stabilizing certain intermediates, thereby facilitating the production of \(\mathrm{ClO}_{2}\). By understanding how acidic solutions influence reactions, one can manipulate the conditions to achieve optimal results in chemical synthesis.

Decontaminating Agent

Chlorine dioxide \((\mathrm{ClO}_{2})\) is widely recognized as an effective decontaminating agent. Its ability to neutralize pathogens and pollutants makes it indispensable in sanitation.
Notable uses of \(\mathrm{ClO}_{2}\) as a decontaminant include:

• Water treatment processes, ensuring safe and clean drinking water.
• Food processing, where it helps eliminate microbes that can spoil food or cause illness.
• Healthcare settings, providing disinfection of medical instruments and surfaces.

The efficacy of \(\mathrm{ClO}_{2}\) lies in its broad-spectrum action, as it remains potent against a wide range of microorganisms without compromising safety. Its usage as a decontaminating agent underscores its critical role in ensuring human health and environmental safety.