A soft drink was bottled with a partial pressure of $CO_2$ of 3 bar over the liquid at room temperature. The partial pressure of $CO_2$ over the solution approaches a value of 30 bar when 44 g of $CO_2$ is dissolved in 1 kg of water at room temperature. The approximate pH of the soft drink is $\underline{\hspace{2cm}}\times$ 10–1. (First dissociation constant of $H_2CO_3$ = 4.0 $\times$ 10–7; log 2 = 0.3; density of the soft drink = 1 g mL–1) .