What Is The PH Of A Solution Of Sodium Hydrosulfite?

Sodium hydrosulfite is a basic compound that can react with water to produce hydroxide ions (OH-) and sulfurous acid (H2SO3). The pH of a solution of sodium hydrosulfite will depend on the concentration of the compound and the amount of sulfurous acid formed in the solution.

At a concentration of 0.1 M, the pH of a solution of sodium hydrosulfite is expected to be around 11. At this concentration, the hydroxide ions produced by the reaction of the compound with water will dominate the solution, leading to an increase in pH.

However, at higher concentrations, the production of sulfurous acid will also contribute to the overall pH of the solution. Under acidic conditions, sulfurous acid will exist predominantly in its undissociated form, which means that it will not contribute significantly to the pH of the solution. However, as the solution becomes more alkaline, sulfurous acid will dissociate into sulfite ions (SO32-) and hydrogen ions (H+), which will lower the pH of the solution.

Therefore, the pH of a solution of sodium hydrosulfite cannot be determined solely by the concentration of the compound. Other factors such as temperature, pressure, and the presence of other chemical species in the solution could also influence the pH value.