GKFix MCQ Question

What is the concentration of S²⁻ in a 0.1 M H₂S solution if Ka₁ = 9.1 × 10⁻⁸ and Ka₂ = 1.2 × 10⁻¹³?

• A. 1.2 × 10⁻¹³ M
• B. 9.1 × 10⁻⁸ M
• C. 1.092 × 10⁻²⁰ M
• D. 6.0 × 10⁻¹⁰ M