Hydrogen water is regular water that has been infused with extra molecular hydrogen gas (H₂), which is a tasteless, colorless, and odorless substance. The water itself, with its familiar chemical structure of H₂O, is simply augmented by the dissolved gas. To understand the properties of this modified water, it is important to first establish what pH measures and how dissolved gases typically interact with water chemistry. This article will provide the scientific details regarding the pH of hydrogen water and distinguish it from other popular forms of drinking water.
What pH Measures and How Gases Interact With Water
The pH scale is a logarithmic measure used to specify the acidity or alkalinity of an aqueous solution, ranging from 0 to 14. A value of 7 is considered neutral, while values below 7 indicate increasing acidity and values above 7 indicate increasing alkalinity. This measurement is directly tied to the concentration of free hydrogen ions (H⁺) and hydroxide ions (OH⁻) in the water.
To change the pH of water, a dissolved substance must undergo ionization, meaning it must dissociate into H⁺ or OH⁻ ions upon mixing with water. For example, carbon dioxide (CO₂) is a gas that significantly alters pH when dissolved in water. The CO₂ reacts with water to form carbonic acid (H₂CO₃), which then releases hydrogen ions (H⁺) into the solution. The release of these hydrogen ions increases the overall acidity of the water, thus lowering the pH. This process is why carbonated beverages have a slightly acidic pH.
The Direct Answer: pH Neutrality of Hydrogen Water
The pH of hydrogen water is essentially neutral, meaning it is the same as the starting water used in the infusion process, typically around a pH of 7. The reason for this neutrality lies in the chemical nature of molecular hydrogen (H₂). Molecular hydrogen is a non-polar, highly stable, and relatively inert gas.
When H₂ gas is dissolved into water, it does not react with the water molecules to produce H⁺ or OH⁻ ions. Unlike carbon dioxide, the H₂ molecule remains intact and does not undergo ionization within the water. The delicate balance of existing hydrogen and hydroxide ions is therefore not disturbed by the presence of the dissolved hydrogen gas.
The methods used to create hydrogen water, such as infusion under pressure or electrolysis, are designed to maximize the concentration of the dissolved H₂ gas. If the process is done correctly, these methods introduce only the neutral gas and no other pH-altering substances. Therefore, the resulting hydrogen water will maintain the original pH of the source water.
This lack of chemical reaction is a defining characteristic of molecular hydrogen when dissolved in water. The stability of the H₂ molecule ensures that the water’s acid-base status remains unchanged.
Why Hydrogen Water Is Not the Same as Alkaline Water
A common consumer misconception is that hydrogen water is a type of alkaline water, but they are chemically distinct products. Alkaline water is defined by its high pH, which typically ranges from 8 to 10. This higher pH is achieved by increasing the concentration of hydroxide ions (OH⁻) in the water.
This increase in alkalinity is generally accomplished by dissolving alkaline minerals, such as calcium, magnesium, or potassium, into the water. These minerals act as buffers or sources of hydroxide ions, which raise the pH level significantly above the neutral point of 7.
In contrast, hydrogen water’s defining feature is the presence of the dissolved H₂ gas, with its pH remaining neutral. Hydrogen water provides molecular hydrogen, while alkaline water provides a higher pH and dissolved alkaline minerals.