pH 7 corresponds to which type of solution?

pH 7 corresponds to which type of solution?

• A. Strong acid
• B. Weak acid
• C. Neutral
• D. Weak alkali

Answer: (C)

A pH of 7 indicates a neutral solution, where hydrogen ions and hydroxide ions are present in equal amounts. At room temperature in pure water, [H+] = [OH−] = 1×10⁻⁷ M, giving pH = −log10(1×10⁻⁷) = 7. This means the solution is neither acidic nor basic. Strong or weak acids have more H+ than OH− and thus pH values below 7, while alkalis (bases) have more OH− than H+ and a pH above 7. So pH 7 specifically points to neutrality.

A pH of 7 indicates a neutral solution, where hydrogen ions and hydroxide ions are present in equal amounts. At room temperature in pure water, [H+] = [OH−] = 1×10⁻⁷ M, giving pH = −log10(1×10⁻⁷) = 7. This means the solution is neither acidic nor basic. Strong or weak acids have more H+ than OH− and thus pH values below 7, while alkalis (bases) have more OH− than H+ and a pH above 7. So pH 7 specifically points to neutrality.