Final answer:
In a 0.050M solution of 3H2SO3, the pH is determined by the concentration of hydrogen ions (H+), which is 0.100M. The concentrations of HSO63− and SO32− in this solution are both 0.050M. In a 0.050M solution of NaHSO3, the pH is determined by the concentration of hydronium ions (H3O+), which is also 0.050M. The concentrations of HSO63− and OH− in this solution are also 0.050M. In a 0.050M solution of Na2SO3, the pH is determined by the concentration of hydroxide ions (OH−), which is 0.050M. The concentration of HSO63− in this solution is also 0.050M.
Step-by-step explanation:
Let's calculate the pH and the concentrations of H2SO3 (sulfurous acid), HSO3- (hydrogen sulfite ion), and SO32- (sulfite ion) in each solution:
a) 0.050M 3H2SO3
The pH:
Since H2SO3 is a weak acid, it partially dissociates in water:
H2SO3 <==> 2H+ + SO32-
According to the equation above, the concentration of H2SO3 is double the concentration of H+. Therefore, the pH of the solution is determined by the concentration of H+.
Now, we need to find the concentration of H+:
[H+] = 2 × 0.050M = 0.100M
Concentrations of HSO3- and SO32-:
The concentrations of HSO3- and SO32- are both equal to 0.050M, as they are formed in a 1:1 ratio with H2SO3. Therefore, [HSO3-] = [SO32-] = 0.050M.
b) 0.050M NaHSO3
The pH:
NaHSO3 is a salt of a weak acid (HSO3-) and a strong base (NaOH). The hydrolysis of the anion HSO3- in water results in the formation of hydronium ions (H3O+) and hydroxide ions (OH-). Since H3O+ is the stronger acid, it determines the pH of the solution.
Therefore, the pH of the solution can be found by calculating the concentration of H3O+.
Concentrations of HSO3-, H3O+, and OH-:
The concentration of HSO3- is equal to the initial concentration of NaHSO3, which is 0.050M.
Since NaHSO3 is a salt of a weak acid and a strong base, it undergoes hydrolysis. The anion HSO3- acts as a weak acid and the resulting hydronium ion concentration is equal to the concentration of OH-.
Therefore, [HSO3-] = [H3O+] = [OH-] = 0.050M.
c) 0.050M Na2SO3
The pH:
Na2SO3 is a salt of a strong base (NaOH) and a weak acid (SO32-). Since NaOH is a strong base, it completely dissociates in water, resulting in the formation of hydroxide ions (OH-). The pH of the solution can be determined by calculating the concentration of OH-.
Concentrations of SO32- and OH-:
The concentration of SO32- is equal to the initial concentration of Na2SO3, which is 0.050M.
Since Na2SO3 is a salt of a strong base and a weak acid, it undergoes hydrolysis. The anion SO32- acts as a weak base and the resulting hydroxide ion concentration is equal to the concentration of SO32-.
Therefore, [SO32-] = [OH-] = 0.050M.