Chapter 15, Problem 15.22A

APPLY 15.22 Carbonated drinks are prepared by dissolving CO₂ under high pressure. CO₂ reacts with water to product carbonic acid according to the equation:

${\text{CO}}_{\text{2}}\left(g\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\rightleftharpoons {\text{CO}}_{\text{2}}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\rightleftharpoons {\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}\left(aq\right)$

Assume all the dissolved CO₂ is converted to H₂CO₃. Calculate the pH and the concentrations of all species present (H₂CO₃ HCO₃^-, CO₃^2-, H₃O⁺, and OH^-) in a can of carbonated water with a partial pressure of CO₂ of 4.5 atm. The solubility of a gas can be calculated from Henry’s Law, Solubility = k • P (Section 12.4). The Henry’s Law constant (k) for CO₂, at 25°C is 3.2 × 10-2 mol/(L • atm) and K_avalues for H₂CO₃ are in Table 15.3.