15.5 Concentrated aqueous HCl has a concentration of 12.1 M . Calculate the concentrations of all ions present in a solution prepared by
pipetting 1.00 mL of concentrated HCl into a 100 mL volumetric flask and filling to the mark.

When you pipette 1.00 mL of 12.1 M HCl into a 100 mL volumetric flask, you are diluting the concentrated solution. To calculate the final concentration of the HCl solution, you can use the dilution formula, . Here, is the initial concentration (12.1 M), is the initial volume (1 mL), is the final concentration, and is the final volume (100 mL).

Plugging in the values:

Since hydrochloric acid (HCl) completely dissociates in water, the concentration of H ions and Cl ions in the solution will also be 0.121 M. Thus, we have:

This shows that in a diluted solution, the ions maintain the same stoichiometric ratio as present in the original compound!

Isn’t it amazing how a simple equation can take concentrated acid and deliver pure clarity on ion concentrations? It’s like mixing cocktails in chemistry, where a bit of HCl can turn into two equally refreshing beverages: H and Cl ! Just remember, when playing with acids, safety first—always wear safety goggles and gloves!

For further exploration, you might find it fascinating to learn about other strong acids and their behaviors in solution. Experimenting with different concentrations or even diluting other acids like sulfuric or nitric can reveal how they compare in terms of ion concentration and dissociation, adding a splash of variety to your chemistry journey!