The [H+] concentration of a solution is 3.8 × 10⁻² M. Calculate the pH of this solution. (Given that log₁₀ 3.8 = 0.58).

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Points to Remember:

  • pH is a measure of the acidity or basicity of a solution.
  • pH = -log₁₀[H⁺], where [H⁺] is the hydrogen ion concentration.
  • A lower pH indicates a more acidic solution, while a higher pH indicates a more basic solution.

Introduction:

The pH scale is a logarithmic scale used to specify the acidity or basicity (alkalinity) of an aqueous solution. It ranges from 0 to 14, with 7 being neutral. Solutions with a pH less than 7 are acidic, and solutions with a pH greater than 7 are basic (alkaline). The pH is defined as the negative base-10 logarithm of the hydrogen ion concentration ([H⁺]) in moles per liter (M). This question requires a straightforward calculation using the given hydrogen ion concentration and the provided logarithm value.

Body:

Calculating the pH:

The given hydrogen ion concentration [H⁺] is 3.8 × 10⁻² M. To calculate the pH, we use the formula:

pH = -log₁₀[H⁺]

Substituting the given value:

pH = -log₁₀(3.8 × 10⁻²)

Using the logarithm property log(a × b) = log(a) + log(b), we can rewrite the equation as:

pH = -[log₁₀(3.8) + log₁₀(10⁻²)]

We are given that log₁₀(3.8) = 0.58. Also, log₁₀(10⁻²) = -2. Therefore:

pH = -(0.58 – 2)

pH = -(-1.42)

pH = 1.42

Interpretation of the Result:

The calculated pH of the solution is 1.42. Since this value is less than 7, the solution is acidic. A pH of 1.42 indicates a relatively strong acidic solution. Examples of substances with similar pH values include strong acids like gastric acid.

Conclusion:

The pH of the solution with a hydrogen ion concentration of 3.8 × 10⁻² M is calculated to be 1.42. This signifies a strongly acidic solution. The calculation involved a straightforward application of the pH formula and the properties of logarithms. Understanding pH calculations is crucial in various fields, including chemistry, environmental science, and biology, for assessing the properties and potential impacts of solutions. Further analysis might involve comparing this pH to regulatory limits for specific applications or exploring the effects of this acidity on different materials or biological systems. Accurate pH measurement and calculation are essential for maintaining safety and ensuring the quality of various processes and products.

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