Final answer:
A decrease in pH from 8 to 6 indicates an increase in the acidity of the solution, meaning the concentration of hydronium ions has increased and the solution's acidity is now 100 times greater.
Step-by-step explanation:
If the pH of a solution is decreased from pH 8 to pH 6, it means that the concentration of hydronium ions ([H3O+]) has increased. The pH scale is logarithmic, which means each whole pH value below 7 is ten times more acidic than the next higher value. Therefore, decreasing the pH from 8 to 6 indicates that the solution's acidity has increased by 100 times because pH 6 is two whole pH units lower than pH 8. This is based on the definition that a pH less than 7 is considered acidic, a pH equal to 7 is neutral, and a pH greater than 7 is basic. As the solution moves from a pH of 8 to a pH of 6, it moves from a basic to a more acidic pH range. A good example to understand this concept is the addition of acid to water; as the acid concentration increases, the pH decreases accordingly.