A blood pH is called acidosis when it is lower than the normal range, which is typically between 7.35 and 7.45.

Here's why this is the case:

* pH Scale: The pH scale measures the acidity or alkalinity of a solution. A pH of 7 is neutral, below 7 is acidic, and above 7 is alkaline (basic).

* Hydrogen Ions: Acidity is determined by the concentration of hydrogen ions (H+) in a solution. The more H+ ions present, the more acidic the solution.

* Blood pH and Acidosis: In acidosis, there's an increase in the concentration of hydrogen ions in the blood, making it more acidic. This can be caused by various factors, such as:

* Metabolic Acidosis: The body produces too much acid or fails to eliminate enough acid.

* Respiratory Acidosis: The lungs fail to eliminate enough carbon dioxide, which is acidic.

Important Note: Acidosis is a serious medical condition that requires immediate medical attention. If you suspect you or someone you know may have acidosis, seek medical help immediately.