Sodium bicarbonate, commonly known as baking soda, is a simple substance often used in cooking and cleaning. Dissolving baking soda in water does raise the pH, moving the solution from neutral toward the alkaline side of the scale (above 7).
The Chemical Process of Alkalization
When sodium bicarbonate dissolves in water, it dissociates into a sodium ion (Na+) and a bicarbonate ion (HCO3-). The bicarbonate ion is the chemical component responsible for increasing alkalinity.
The bicarbonate ion acts as a weak base, meaning it can accept a hydrogen ion (H+) from the surrounding water molecules. By removing hydrogen ions, the relative concentration of hydroxide ions (OH-) in the solution increases. This shift in the balance of ions is what chemically defines a base and, consequently, an increase in pH. The pH scale ranges from 0 to 14, with 7 being neutral. Because of the weak basic nature of the bicarbonate ion, a typical solution of baking soda and water will stabilize at a mildly alkaline pH, often around 8.3 to 8.5.
Practical pH Measurement and Adjustment
Altering the pH of water with baking soda requires only a small dosage, as the substance is quite effective at neutralizing acidity. For example, to adjust the pH of a liter of water from slightly acidic (pH 6) to neutral (pH 7), only about 0.6 grams, or roughly 0.12 teaspoons, of baking soda may be necessary. The exact amount needed will depend on the initial mineral content and buffering capacity of the water source.
The bicarbonate ion also acts as a buffer, meaning it resists large, sudden changes in pH. This helps stabilize the water’s pH within a certain range, preventing it from becoming excessively alkaline. Individuals can monitor the resulting pH change using simple tools like pH test strips or a digital pH meter.
Common Applications and Safety Guidelines
People often alkalize water with baking soda for specific health purposes, such as alleviating the symptoms of acid reflux or indigestion. The alkaline solution works as a temporary antacid by helping to neutralize excess stomach acid. Sodium bicarbonate is also sometimes used in certain athletic circles, where it is thought to help buffer lactic acid buildup in muscles, potentially delaying fatigue.
Beyond personal consumption, baking soda is used to adjust the pH of water in systems like swimming pools or garden ponds. Raising a low pH level to a more balanced range is beneficial for equipment and aquatic life. However, when consuming this solution, it is important to follow safety guidelines.
Baking soda contains a significant amount of sodium, with just one teaspoon containing about 1200 milligrams. For healthy adults, short-term, small doses—such as a limit of a half-teaspoon per serving—are generally considered safe. Individuals on a sodium-restricted diet, or those with existing conditions like heart or kidney disease, should avoid consuming baking soda water unless specifically advised by a healthcare professional. Excessive or long-term consumption can lead to side effects like metabolic alkalosis, a condition where the body’s blood pH becomes too alkaline.