Problem 22 - Chemistry The Molecular Science

Question

Amantadine, \(\mathrm{C}_{10} \mathrm{H}_{15} \mathrm{NH}_{2}\), is a base used to treat Parkinson's disease. Write a balanced chemical equation to represent why an aqueous solution of amantadine is basic.

Step-by-Step Solution

Answer

Amantadine acts as a base by accepting a proton from water, forming \( ext{OH}^-\) ions.

Step 1: Identify the chemical formula of amantadine

Amantadine is represented by the chemical formula \( ext{C}_{10} ext{H}_{15} ext{NH}_{2}\). This formula tells us that it contains an amine group \( ext{-NH}_2\), which is responsible for its basic properties in aqueous solutions.

Step 2: Recognize the nature of amantadine in water

Amantadine, when dissolved in water, acts like a base due to the amine group \( ext{-NH}_2\). This group can accept protons (H\(^+\) ions) from water molecules.

Step 3: Write the equation for the dissociation in water

The amine group \( ext{-NH}_2\) can accept a proton from water, which can be represented by the following equation: \\( ext{C}_{10} ext{H}_{15} ext{NH}_2 + ext{H}_2 ext{O} ightarrow ext{C}_{10} ext{H}_{15} ext{NH}_3^+ + ext{OH}^-\)This equation shows that amantadine takes a proton from water, creating hydroxide ions \( ext{OH}^-\), which demonstrate its basicity.

Step 4: Confirm the equation is balanced

The equation \( ext{C}_{10} ext{H}_{15} ext{NH}_2 + ext{H}_2 ext{O} ightarrow ext{C}_{10} ext{H}_{15} ext{NH}_3^+ + ext{OH}^-\) is balanced in terms of atoms and charge. Each side of the equation has the same number of each type of atom, and the total charges on both sides are equal.

Key Concepts

Basic Solutions

A basic solution is one in which the concentration of hydroxide ions overbalance the concentration of hydrogen ions. This typically happens when compounds dissolve in water and release or form hydroxide ions (\(\text{OH}^-\)). Such solutions have a pH greater than 7.

• In the case of amantadine, the amine group \(-\text{NH}_2\) plays a crucial role in creating a basic solution.
• When added to water, it increases the \(\text{OH}^-\) concentration.

Amantadine's basicity is attributed to the amine's ability to accept protons from water, which will be further explained in the next sections.

Chemical Equations

Writing chemical equations is fundamental to understanding how substances interact in a reaction. These equations must be balanced for both mass and charge to accurately represent reality.

• For amantadine, the chemical equation illustrating its basic nature is:
• \(\text{C}_{10}\text{H}_{15}\text{NH}_{2} + \text{H}_{2}\text{O} \rightarrow \text{C}_{10}\text{H}_{15}\text{NH}_{3}^+ + \text{OH}^-\)
• This equation reflects that amantadine accepts a proton from water, forming a positively charged ammonium ion and a hydroxide ion.

Balancing ensures that the same number of each type of atom appears on both sides of the equation, preserving the law of conservation of mass. Additionally, charge neutrality is maintained as the total charge is identical for both the reactants and products.

Proton Acceptance

Proton acceptance is a process where a molecule or ion takes a hydrogen ion \((\text{H}^+)\) from another substance.

• The ability of amantadine to accept protrons stems from the amine group.
• When the amine group \(-\text{NH}_2\) in amantadine accepts a proton from water, it turns into \(\text{NH}_3^+\).

This transformation is essential in establishing the basic nature of amantadine in a solution.
When protons are accepted, water molecules effectively release hydroxide ions \(\text{OH}^-\), further contributing to the solution's basicity.