Question

In aqueous solution the ionization constants for carbonic acid are

K₁ = 4.2 x 10^–7 and K₂ = 4.8 x 10^–11 

Select the correct statement for a saturated 0.034 M solution of the carbonic acid.

(1) The concentration of CO₃^2- is 0.034 M.

(2) The concentration of CO₃^2- is greater than that of HCO₃^- .

(3) The concentration of H⁺ and HCO₃^- are approximately equal.

(4) The concentration of H⁺ is double that of CO₃^2- .

Answer 1

(3) 

[CO₃^2-] is negligible compared to [HCO₃^-] or [H⁺]_total