Determine the Ka of an aqueous HZ, a weak acid, prepared by dissolving 0. 020 mol of HZ in sufficient water to yield 1. 0 L of solution. The pH of the solution was 4. 93 at 25. 0 °C.
A. 6. 9x10⁻⁹
B. 1. 4x10⁻¹⁰
C. 2. 8x10⁻¹²
D. 9. 9x10⁻²