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 44g  of CO2  is dissolved in 1 kg of water at room temperature. The approximate pH of the soft drink is ______×10−1(First dissociation constant of H2CO3=4.0×10−7;log2=0.3; density of the soft drink =1 g  mL−1)