A soft drink was bottled with a partial pressure of CO₂ of 3 bar over the liquid at room temperature. The partial pressure of CO₂ over the solution approaches a value of 30 bar when 44 g of CO₂ is dissolved in 1 kg of water at room temperature. The approximate pH of the soft drink is ______ $\times$ 10^–1.
(First dissociation constant of
H₂CO₃ = 4.0 $\times$ 10^–7; log 2 = 0.3; density
of the soft drink = 1 g mL^–1) .