What is true for a solution with a pH less than 7?

A solution with a pH less than 7 is defined as acidic. The pH scale, which ranges from 0 to 14, indicates the concentration of hydrogen ions (H+) in a solution. A pH of 7 is considered neutral, meaning the concentrations of hydrogen ions and hydroxide ions (OH-) are equal. When the pH is below 7, it signifies that the concentration of hydrogen ions is greater than that of hydroxide ions, which is characteristic of acid solutions.

For example, a pH of 6 indicates a higher presence of H+ ions compared to OH- ions, while a pH of 5 would represent an even higher concentration of H+. Solutions such as vinegar or lemon juice, which are acidic, typically have pH values lower than 7, confirming this relationship between pH and acidity. Hence, the statement that a solution with a pH less than 7 is acidic aligns perfectly with the definitions and principles of acid-base chemistry.