Question

Calculate [H₃O+] and [S²⁻] in a 0.1 M solution of the diprotic acid hydrosulfuric acid. (For hydrosulfuric acid Ka1 = 9.0x10⁻⁸ and Ka2 = 1.0x10⁻¹⁷.) Enter your answers in scientific notation.

Answer 1

To calculate the concentrations of [H₃O+] and [S²⁻] in a 0.1 M solution of diprotic acid hydrosulfuric acid, we can approximate [H₃O⁺] to be equal to the initial concentration of hydrosulfuric acid (0.1 M) and [S²⁻] to be equal to the concentration of hydrosulfuric acid (0.1 M).

Step-by-step explanation:

To calculate the concentrations of [H₃O+] and [S²⁻] in a 0.1 M solution of diprotic acid hydrosulfuric acid, we need to consider its two ionization steps. First, we calculate the concentration of [H₃O⁺] using the value of the first dissociation constant (Ka₁ = 9.0x10⁻⁸). Since Ka₁ is much greater than Ka₂, we can approximate [H₃O⁺] to be equal to the initial concentration of hydrosulfuric acid (0.1 M).

For the ionization step that leads to [S²⁻] (Ka₂ = 1.0x10⁻¹⁷), we use the approximation that the concentration of [H₃O⁺] from the dissociation of HS⁻ is negligible compared to that of H₂S. Therefore, [S²⁻] is equal to the concentration of hydrosulfuric acid (0.1 M).