pH is an approximate measure of?

• A. Temperature of the solution
• B. Concentration of solute
• C. How acidic or basic a solution is
• D. Color of the solution

Answer: (C)

pH measures how acidic or basic a solution is, based on the activity of hydrogen ions in the solution. It uses a negative logarithmic scale to express that activity, with around 7 being neutral at standard conditions, below 7 acidic, and above 7 basic. It’s an approximate measure because it reflects hydrogen ion activity rather than just concentration, and ion activity depends on temperature and the presence of other ions in the solution. Temperature can shift the neutral pH point, and interactions between ions (ionic strength) can change readings. Color is not what pH measures, though indicators can reveal pH by changing color.