Question

Other than water, what would you expect to find in the highest concentration in an aqueous solution of KOH? Explain.

Short answer

In an aqueous solution of KOH, other than water, the substances found in the highest concentration would be potassium ions (K+) and hydroxide ions (OH-). This is because KOH dissociates completely in water, resulting in an equal number of K+ ions and OH- ions.

Step-by-step solution

Determining the Solute

First, identify the solute in the solution. From the exercise, an aqueous solution of KOH is provided, where water (H2O) is the solvent and KOH is the solute. Thus, other than water, it becomes apparent that KOH could be the substance found in the highest concentration.

Understanding Dissociation in Solution

When solutes dissolve in water, they undergo a process known as dissociation - where a compound breaks apart into its component ions. Potassium hydroxide (KOH), being a strong base, completely dissociates in water to form potassium ions (K+) and hydroxide ions (OH-).

Writing the Dissociation Equation

Demonstrating this process through a chemical equation would look like this: \[ \text{KOH} \rightarrow \text{K}^+ + \text{OH}^- \] The arrow suggests that KOH dissociates into K+ and OH- ions.

Observing the Ion Concentrations

After dissociation, every molecule of KOH has produced one potassium ion (K+) and one hydroxide ion (OH-). So, after water molecules, the substances present in highest concentration in a solution of KOH would be equal amounts of K+ ions and OH- ions.

Identifying the Final Answer

So, other than water, the substances that would be found in the highest concentration in an aqueous solution of KOH are the potassium ions (K+) and the hydroxide ions (OH-). In conclusion, the substance with the highest concentration in an aqueous solution of KOH, besides water, would be potassium ions (K+) and hydroxide ions (OH-).

Key concepts

Dissociation

Dissociation is a crucial concept in understanding how compounds behave in solutions. It refers to the process where molecules break apart into smaller particles, usually ions, when mixed with a solvent like water. When a solute, such as potassium hydroxide (KOH), is introduced into an aqueous solution, it dissociates into its constituent ions.

This process is captured by a simple reaction: KOH separates to form potassium ions ( K^+ ) and hydroxide ions ( OH^- ).

• Dissociation is important because it helps predict the behavior of substances in a solution.
• The extent of dissociation can affect the chemical properties and reactions within the solution.

Understanding dissociation is key to exploring why certain ions appear in significant concentrations when solutes are dissolved in solvents like water.

Strong Base

A strong base is characterized by its ability to fully dissociate in a solution, releasing ions that make the solution alkaline. Potassium hydroxide (KOH) is a classic example of a strong base. This means that when KOH is dissolved in water, it completely separates into potassium ions ( K^+ ) and hydroxide ions ( OH^- ).

Here's why KOH is considered a strong base:

• Complete dissociation in water, leading to effective ion production.
• High pH levels in solution due to the presence of hydroxide ions ( OH^- ).
• Strong bases have a high capacity to neutralize acids, resulting in the formation of water and a salt in a neutralization reaction.

This complete ion release makes strong bases like KOH very useful in various chemical reactions where pH needs to be managed.

Potassium Ions

Potassium ions ( K^+ ) are one of the two ionic components generated when KOH dissociates in an aqueous solution. Potassium is an essential element, recognized widely for its roles in biological systems, particularly in cellular functions in living organisms.

In the context of solutions:

• Potassium ions maintain electrical neutrality in the solution.
• They are critical in transmitting nerve impulses and muscle contractions in biological systems.
• In a KOH solution, each formula unit yields one K^+ ion, balancing the charge created by the dissociated OH^- ions.

This ion's presence in a KOH aqueous solution significantly affects both the physical and chemical properties of the solution.

Hydroxide Ions

Hydroxide ions ( OH^- ) are produced in equal measure alongside potassium ions when KOH dissociates in water. These ions play a crucial role in making a solution basic or alkaline. They are responsible for increasing the pH of a solution and therefore greatly impact chemical reactions.

Key aspects of hydroxide ions include:

• Their ability to neutralize acids, resulting in water and salt through neutralization reactions.
• They increase the alkalinity of the solution, making it a strong base solution.
• Each molecule of KOH provides one OH^- ion, balancing each K^+ ion.

Understanding hydroxide ions is essential for comprehending how strong bases influence their surroundings, particularly when it comes to balancing pH levels in various solutions.