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Is Distilled Water Acidic Or Basic?
Distilled water is the most chemically pure type of water available, and it is also the safest to consume. Distilled water consists largely of full water molecules with few free ions. It’s less reactive than other liquid substances used for dilution. It is typically employed in chemical research. But is distilled water acidic or basic? Let’s find out!
pH Balance of Water
The negative logarithm of the real hydrogen ion concentration is the word itself, which loosely translates to “power of hydrogen.” Its pH measures the concentration of hydrogen ions in a solution. It indicates that hydrogen ion concentration falls when pH rises. The difference of one pH unit equals a tenfold change in hydrogen ion concentration. pH levels can range from 0 to 14. Acidic solutions have a pH between 0 and 7, while basic solutions have a pH between 7 and 14.
What Are Acids and Bases?
A pH of 7 indicates that the solution is completely neutral. A solution with a pH less than 7 is acidic, whereas one with a pH of more than 7 is alkaline. The further the reading deviates from 7, the more it indicates the liquid as alkaline or acidic.
Acid is a chemical that releases free protons in water according to the popular Bronsted-Lowry Theory of Acids and Bases. A base, on the other hand, is a protons-accepting molecule. Hydrochloric acid and sodium hydroxide are examples of powerful acids and alkalis. The pH of a solution will alter drastically if it adds either of these substances or something comparable.
Is Distilled Water Acidic Or Basic?
Distilled water, a form of purified water, undergoes a process to remove impurities and solutes. This process involves heating the water to a high temperature, allowing the steam to condense in a tube, and collecting the condensation in a container. Distillation effectively removes many compounds from water, retaining salts and other solid solutes. If done correctly, the collected condensate should be free of any solutes and initially have a neutral pH of 7. However, this pH can change quickly due to environmental factors.
The Initial pH of Distilled Water
Pure distilled water should initially have a pH of 7. This neutrality is due to the absence of dissolved substances that could alter its pH. However, as soon as distilled water is exposed to air, it starts to absorb carbon dioxide. This absorption changes the water's pH, making it slightly acidic.
Carbon Dioxide Absorption and pH Change
The pH of distilled water becomes slightly acidic, around 5.8, due to the absorption of carbon dioxide from the atmosphere. When carbon dioxide dissolves in distilled water, it forms a weak solution of carbonic acid, contributing to the water's acidity. This phenomenon is why demineralized water, another type of purified water, reacts poorly with metals such as steel, as the slightly acidic nature can promote corrosion.
The Chemistry Behind pH Reduction
The chemical reaction responsible for this pH change involves the formation of hydronium ions (H3O+) when carbonic acid is produced. The presence of hydronium ions in the solution acts similarly to an influx of free hydrogen ions, lowering the pH level. The relevant chemical reactions can be summarized as follows:
pH Levels of Very Clean Distilled Water
In practice, very clean distilled water that has minimal contact with air tends to have a pH slightly below 7, usually around 6.9. This minor deviation from neutrality does not imply significant acidity. The acidity of distilled water is extremely low, much like that of rainwater, which has a pH of approximately 5.6 due to the same carbon dioxide absorption process. This slight acidity is perfectly safe and not harmful to touch.
Practical Implications
The slightly acidic nature of distilled water has practical implications. For instance, it is often used in laboratory settings where the purity of water is critical. However, its tendency to absorb carbon dioxide and become slightly acidic must be considered, particularly in experiments where pH levels are crucial. Additionally, its corrosive effect on metals suggests that it should be stored and handled in appropriate containers to avoid unwanted reactions.
In conclusion, distilled water starts with a neutral pH of 7, but exposure to air and the absorption of carbon dioxide can lower its pH to around 5.8, making it slightly acidic. This change is a natural consequence of its interaction with the environment and does not pose any significant risk in most practical applications.
What Is The Best Way To Determine The pH Of Distilled Water?
Purified water products, such as distilled or deionized water, rarely, if ever, have a high ionic presence. Determining the pH of distilled water can be extremely difficult because there aren’t enough ions in the solution for the pH electrode to work effectively.
It means that the pH reading of distilled water isn’t always reliable, and you can tell if the readings are fluctuating between figures. Adding a few drops of potassium chloride (KCI) to the solution is one technique to deal with this.
The presence of KCI increases the conductivity of the water. It’s because potassium chloride is an ionic molecule containing both K+ and Cl- ions. Adding this to distilled water before measuring the pH will not change the outcome, making it more stable and likely to yield reliable findings. You can also use sodium chloride (table salt) to make distilled water more conductive.
FINAL THOUGHTS
Is distilled water acidic or basic? With a pH of 7, pure distilled water is considered neutral in science, meaning it is neither acidic nor alkaline. Distilled water is particularly sensitive to the environment due to its high purity. Even a small amount of carbon dioxide from the air can cause it to become mildly acidic.
When you consume distilled water, it mixes with mildly acidic digestive enzymes in your saliva and then with very acidic digestive enzymes in your stomach a few seconds later. The stomach’s far stronger hydrochloric acid has a pH of 1.5 to 3.5, making it 100,000 times more acidic than the purified water with which it reacts.
Awesome Water Filters offers Distillers so you can conveniently make distilled water in the comfort of your homes.