What pH value is considered neutral (neither acidic nor basic)?

• A. 7
• B. 0
• C. 14
• D. 3.9

Answer: (A)

On the pH scale, neutral means the hydrogen ion concentration equals the hydroxide ion concentration, which occurs at pH 7 under standard room conditions. At this point, [H+] and [OH-] are both about 1.0 x 10^-7 M, so the solution is neither acidic nor basic. Values below 7 indicate acidity because there are more H+ ions, while values above 7 indicate basicity because there are more OH- ions. Therefore, 7 is the neutral value, while 0 and 14 are extreme acidic and basic, respectively, and 3.9 is acidic.