4. Calculate the pH of 0.90M HPO4?Ka HPO4^2- = 4.5 x 10-13(a) 7(b) 14(c) 12.3(d) 8.20(e) 6.20

Answer
Explanation
Given:
[H⁺] = 0.90 M
Ka HPO₄²⁻ = 4.5 x 10⁻¹³