Unless you're sick you body maintains your blood pH at 7.4 which is slightly alkaline. A major component of this buffering is the amount of carbon dioxide that is dissolved in your blood serum.
From a practical point of view you have little control of your blood pH no matter what you eat or drink, irrespective of what purveyors of various foods and drinks may seem to claim.
If you are sick and have electrolyte imbalance the best method of correction is IV fluids.