Question

Calculate the \(\mathrm{pOH}\) corresponding to each of the \(\mathrm{pH}\) values listed, and indicate whether each solution is acidic, basic, or neutral. a. \(\mathrm{pH}=1.02\) b. \(\mathrm{pH}=13.4\) c. \(\mathrm{pH}=9.03\) d. \(\mathrm{pH}=7.20\)

Short answer

a. pOH = 12.98, acidic solution b. pOH = 0.6, basic solution c. pOH = 4.97, basic solution d. pOH = 6.80, neutral solution

Step-by-step solution

Calculate pOH values for each pH value given

Using the relationship pH + pOH = 14, we can find the pOH value for each pH: a. pOH = 14 - pH = 14 - 1.02 b. pOH = 14 - pH = 14 - 13.4 c. pOH = 14 - pH = 14 - 9.03 d. pOH = 14 - pH = 14 - 7.20

Evaluate pOH for each case

Now we can calculate the pOH value for each given pH and determine if the solution is acidic, basic, or neutral: a. pOH = 14 - 1.02 = 12.98 (pH < 7, so the solution is acidic) b. pOH = 14 - 13.4 = 0.6 (pH > 7, so the solution is basic) c. pOH = 14 - 9.03 = 4.97 (pH > 7, so the solution is basic) d. pOH = 14 - 7.20 = 6.80 (pH is approximately equal to 7, so the solution is neutral)

Final Answers

After calculating the pOH values and determining the nature of each solution, we have the following results: a. pOH = 12.98, acidic solution b. pOH = 0.6, basic solution c. pOH = 4.97, basic solution d. pOH = 6.80, neutral solution

Key concepts

Understanding Acidic and Basic Solutions

Acidic and basic solutions play a fundamental role in chemistry. They refer to the nature of a solution and are determined by the concentration of hydrogen ions (H\(^+\)) in the solution.

An acidic solution contains a higher concentration of hydrogen ions compared to hydroxide ions (OH\(^-\)). This typically results in a pH value that is less than 7.
Conversely, a basic solution has a lower concentration of hydrogen ions, with more hydroxide ions. Basic solutions have a pH value greater than 7.

It's important to remember:

• If the pH is less than 7, the solution is acidic.
• If the pH is more than 7, the solution is basic.
• If the pH equals 7, the solution is considered neutral.

This simple rule helps identify a solution's nature quickly, aiding in many scientific and real-world applications.

The Concept of pOH Values

The pOH value of a solution is often less discussed than pH, but it is equally important. pOH is a measure of the hydroxide ion concentration, inversely relating to the pH.

The relationship between pH and pOH is quite simple: \[pH + \text{pOH} = 14\] This equation helps to find one value if you have the other. For instance, if you know the pH and need to find the pOH, simply subtract the pH from 14. This method is used in chemistry to measure and understand the basicity or acidity of a solution.

When considering the nature of a solution:

• A low pOH (less than 7) indicates a basic solution.
• A high pOH (more than 7) indicates an acidic solution.
• When the pOH is around 7, it indicates a neutral solution.

Understanding both pH and pOH offers a full picture of a substance's chemistry.

Solution Classification

Classifying a solution into acidic, basic, or neutral is crucial in chemistry. It is done mainly through the pH value but can also be viewed in terms of pOH.

To classify:

• Calculate the pOH if it's not provided. Use the pH-pOH relationship: \( pH + pOH = 14 \). Subtract the given pH from 14 to get the pOH.
• Compare the pOH value to 7. If pOH is less than 7, it's a basic solution; if more than 7, it's an acidic solution. If it equals 7, the solution is neutral.

These steps ensure an accurate understanding of a solution's properties. This classification impacts our comprehension of reactions, solution reactivity, and potential uses in industrial or laboratory settings.