What does a pH lower than 7 suggest?

A pH lower than 7 indicates an acidic solution. The pH scale, which ranges from 0 to 14, is a measure of how acidic or basic a solution is. A pH of 7 is considered neutral, representing pure water, while values below 7 indicate an increase in hydrogen ion concentration, which is characteristic of acids. Consequently, liquids like lemon juice and vinegar, which have pH values less than 7, are classified as acids due to their ability to donate protons (H+ ions) to other substances.

In contrast, a solution with a pH above 7 is considered basic or alkaline, and salts are typically neutral when dissolved in water, maintaining a pH of around 7. Therefore, the correct interpretation of a pH lower than 7 is that the solution is acidic.