The pH scale

Understanding the pH Scale

• The pH scale is a measure of how acidic or basic a substance is.
• It ranges from 0 to 14.
• On this scale, 7 is considered neutral. This value is typically achieved by pure water at 25 degrees Celsius.
• Values below 7 represent an acidic environment, while values above 7 indicate a basic or alkaline environment.

Interpreting pH Values

• A difference of one pH unit translates to a tenfold difference in hydrogen ion concentration.
• Substances with a pH of 2 are ten times more acidic than those with a pH of 3 and a hundred times more acidic than substances with a pH of 4.
• Similarly, substances with a pH of 9 are ten times more alkaline than those with a pH of 8.

Changes in pH Values

• Certain substances, known as buffers, can resist changes in pH. These are valuable in processes such as homeostasis in the body or maintaining the quality of certain products.
• Changing temperature can also alter the pH value of a substance.

Measuring pH

• Universal indicator or pH paper can be used to measure the pH of a substance, changing colour depending on the acidity or alkali-ness.
• Precision measurements can also be conducted with more sophisticated equipment, such as a pH meter.