Which pH indicates acidity?

• A. pH greater than 7
• B. pH equal to 7
• C. pH less than 7
• D. pH around 14

Answer: (C)

Acidity is indicated by a pH less than 7. The pH scale shows how concentrated the hydrogen ions are: lower numbers mean more H+, so the solution is acidic. Neutral solutions sit at pH 7, and anything above 7 is basic (alkaline). A pH around 14 is a strongly basic condition, not acidic. So the statement that pH less than 7 denotes acidity is the best answer. For context, common acidic liquids like lemon juice or vinegar have pH values well below 7, while pure water is around 7 and household cleaners are well above 7.