91Ó°ÊÓ

Dilution is a process where the concentration of a solute in a solution is reduced by adding more solvent. This allows us to create a solution of desired concentration by simply adding more of the solvent, often water, to the original solution. When we dilute a solution, the total number of solute particles remains the same, but they are spread out over a larger volume of solvent, leading to a decrease in concentration. In the context of the exercise, you start with a concentrated HCl solution and dilute it with distilled water to reduce its pH from 1 to 2. This involves making the hydronium ion concentration less, which corresponds to a more dilute acid solution.

HCl, or hydrochloric acid, is a strong acid that dissociates completely in water. This means that when you have an HCl solution, it readily gives up its hydrogen ions (H+) to form hydronium ions ({\( H_3O^+ \) }).For instance, in the initial solution provided in the exercise, an HCl solution with a pH of 1 implies a very high hydronium ion concentration, specifically 0.1 M.Understanding how HCl behaves in solution helps in predicting how its acidity changes during dilution, as it directly relates to the change in concentration of {\( H_3O^+ \)} ions. With a reduction in pH, we observe a tenfold decrease in the hydronium ion concentration with each pH unit increase, indicative of the logarithmic nature of the pH scale.

The hydronium ion concentration ({\( H_3O^+ \)}) essentially governs the acidity of a solution. It is closely linked to the pH of the solution, which is calculated using the formula:\[ pH = -\log[H_3O^+] \]From this equation, we can find out how acidic or basic a solution is based on the concentration of hydronium ions present. To convert a solution from one pH level to another, as in our exercise, you change this concentration. For example, going from pH 1 to pH 2 means reducing {\( H_3O^+ \)} by a factor of ten, lowering it from 0.1 M to 0.01 M.

Distilled water is pure water that contains no dissolved salts, minerals, or impurities. It is often used as a solvent in chemical reactions because it does not introduce any additional ions into the solution. In dilution processes, such as those involving hydrochloric acid, distilled water is ideal because it does not alter the chemical composition of the solution other than decreasing the concentration of the solute. This property makes distilled water perfect for achieving precise dilutions, like those required to change the pH of the HCl solution from 1 to 2 by carefully adding 9 liters to dilute the initial concentration of hydronium ions.