Calculate the pH of 0.1M HCl.

To find the pH of a 0.1 M solution of hydrochloric acid (HCl), we first need to understand how strong acids behave in water. HCl is a strong acid, meaning it completely dissociates into its ions when dissolved. This dissociation can be represented by the following equation:

Dissociation of HCl

When HCl is added to water, it dissociates as follows:

• HCl → H⁺ + Cl^-

In a 0.1 M solution of HCl, the concentration of hydrogen ions (H⁺) produced will be equal to the concentration of the acid itself, which is 0.1 M. Therefore, [H⁺] = 0.1 M.

Calculating pH

The pH of a solution is calculated using the formula:

• pH = -log[H⁺]

Substituting the concentration of hydrogen ions into the formula gives us:

pH = -log(0.1)

Using Logarithms

To compute this, we can use the properties of logarithms. The logarithm of 0.1 (which is 10^-1) is -1. Thus:

pH = -(-1) = 1

Final Result

The pH of a 0.1 M solution of HCl is therefore 1. This indicates a highly acidic solution, which is consistent with the properties of strong acids. Remember, the lower the pH, the more acidic the solution is, and a pH of 1 is quite acidic!

Practical Implications

Understanding pH is crucial in various fields, including chemistry, biology, and environmental science. For example, in biological systems, maintaining a specific pH range is vital for enzyme activity and overall cellular function. In environmental contexts, pH can affect the solubility of nutrients and toxins in water, impacting aquatic life.

In summary, the pH of a 0.1 M HCl solution is 1, reflecting its strong acidic nature and complete dissociation in water. This concept is fundamental in acid-base chemistry and has numerous applications in both laboratory and real-world scenarios.