Sodium bicarbonate is a salt that is composed of sodium ions (Na+) and bicarbonate ions (HCO3-). In water, sodium bicarbonate undergoes hydrolysis, in which the bicarbonate ions react with water to form carbonic acid (H2CO3) and hydroxide ions (OH-). The carbonic acid then dissociates to form hydrogen ions (H+) and bicarbonate ions. The hydroxide ions increase the pH of the solution, while the hydrogen ions decrease the pH. The overall effect of sodium bicarbonate on the pH of a solution depends on the concentration of the salt and the temperature of the solution. In general, sodium bicarbonate solutions have a pH between 8.0 and 10.0.