The pH of Distilled Water Placed in an Open Vessel

by

The pH of distilled water placed in an open vessel changes over time due to the absorption of carbon dioxide from the atmosphere. Initially, the pH of distilled water is neutral, around 7. However, as it interacts with the air, it absorbs CO2, which reacts with water to form carbonic acid, releasing hydrogen ions and making the water slightly acidic. This process typically takes about two hours to reach equilibrium, resulting in a pH of around 5.8.

Factors Contributing to pH Change

  1. Carbon Dioxide Absorption: The primary factor contributing to the pH change is the absorption of carbon dioxide from the atmosphere. This reaction forms carbonic acid, which increases the concentration of hydrogen ions, making the water acidic.
  2. Air Exposure: The longer the distilled water is exposed to air, the more CO2 it absorbs, leading to a greater decrease in pH.
  3. Temperature and Pressure: Changes in temperature and pressure can affect the rate of CO2 absorption and the subsequent pH change.

Contaminants and Chemicals Present

ph of distilled water placed in open vessel

  1. Carbon Dioxide: The primary contaminant affecting the pH of distilled water is carbon dioxide from the atmosphere.
  2. Carbonic Acid: The reaction of CO2 with water forms carbonic acid, which contributes to the acidity of the water.
  3. Hydronium Ions: The presence of hydronium ions (H3O+) indicates the acidity of the water.

Dealing with pH Change and Contaminants

  1. Minimizing Air Exposure: Store distilled water in airtight containers to reduce CO2 absorption and minimize pH change.
  2. Using pH Buffers: Adding pH buffers can help maintain a stable pH level by neutralizing the effects of CO2 absorption.
  3. Regular Testing and Monitoring: Regularly test and monitor the pH of distilled water to ensure it remains within the desired range.
See also  The pH of Potassium Iodide in Water

Helpful pH Quantity to Consume and Balancing

  1. Neutral pH: For human consumption, a neutral pH of around 7 is ideal. This can be achieved by using distilled water immediately after distillation or by adding pH buffers to maintain neutrality.
  2. Balancing pH: To balance the pH of distilled water, add small amounts of alkaline substances like sodium hydroxide (NaOH) or calcium hydroxide (Ca(OH)2) to counteract the acidity caused by CO2 absorption.

History and Importance of pH Control

  1. Historical Significance: The concept of pH was first introduced by Søren Sørensen in 1909. It has since become a crucial parameter in various fields, including chemistry, biology, and medicine.
  2. Importance in Medicine: pH control is critical in medical applications, as it affects the efficacy and safety of medications and biological processes.

References

  1. Awesome Water Filters. (2021, September 27). pH of Distilled Water: Understanding Its Importance. Retrieved from https://www.awesomewaterfilters.com.au/blogs/news/what-is-the-ph-of-distilled-water
  2. Sciencing. (2018, April 16). What Is the pH of Distilled Water? Retrieved from https://sciencing.com/ph-distilled-water-4623914.html
  3. Camlab. What is the pH of distilled water? Retrieved from https://www.camlab.co.uk/blog/testing-the-ph-of-distilled-water
  4. Aquapap. (2022, April 7). What is the pH of Distilled Water. Retrieved from https://aquapap.com/what-is-the-ph-of-distilled-water/
  5. Reddit. (2023, September 11). Distilled water pH. Retrieved from https://www.reddit.com/r/chemistry/comments/16g727e/distilled_water_ph/.