Ch.10 Acids and Bases and Equilibrium

Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 14th Edition

Timberlake14th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9781292472249Not the one you use?Change textbook

Timberlake 14th Edition

Ch.10 Acids and Bases and Equilibrium

Problem 39c

Chapter 10, Problem 39c

Calculate the pH of each solution given the following:
c. [OH^-] = 1 × 10^-5 M

Verified step by step guidance

Step 1: Recall the relationship between pH, pOH, and the concentration of hydroxide ions ([OH⁻]). The formula to calculate pOH is:

pOH = - \log ({[OH]}_{-})

Step 2: Substitute the given [OH⁻] value (1 x 10⁻⁵ M) into the formula for pOH. This will give you the pOH of the solution.

Step 3: Use the relationship between pH and pOH, which is:

pH + pOH = 14

. Rearrange this equation to solve for pH:

pH = 14 - pOH

Step 4: Substitute the calculated pOH value from Step 2 into the equation for pH to determine the pH of the solution.

Step 5: Verify your result to ensure it makes sense. Since the [OH⁻] concentration is greater than 1 x 10⁻⁷ M, the solution is basic, and the pH should be greater than 7.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

pH Scale

The pH scale measures the acidity or basicity of a solution, ranging from 0 to 14. A pH of 7 is considered neutral, while values below 7 indicate acidity and values above 7 indicate alkalinity. The scale is logarithmic, meaning each whole number change represents a tenfold change in hydrogen ion concentration.

Hydroxide Ion Concentration

Hydroxide ions (OH⁻) are negatively charged ions that play a crucial role in determining the basicity of a solution. The concentration of hydroxide ions can be used to calculate the pOH of a solution, which is related to pH through the equation pH + pOH = 14. Understanding the concentration of OH⁻ is essential for calculating the corresponding pH.

Relationship Between pH and pOH

The relationship between pH and pOH is fundamental in acid-base chemistry. The pH is derived from the concentration of hydrogen ions (H⁺), while pOH is derived from hydroxide ions (OH⁻). The equation pH + pOH = 14 allows for the conversion between these two measures, enabling the calculation of pH when given the hydroxide ion concentration.

Calculate the pH of each solution given the following:c. [OH-] = 1 × 10-5 M