What is the approximate pH of a neutral salt solution?

The correct answer is Equal to 7.

Key Points

• A neutral salt solution has a pH of exactly 7 at standard temperature and pressure (25°C).
• This occurs because the salt is formed from a strong acid and a strong base, which completely neutralize each other.
• Examples of neutral salts include sodium chloride (NaCl) and potassium nitrate (KNO₃).
• The ions of neutral salts do not hydrolyze in water, maintaining a neutral pH in the solution.

Additional Information

• pH Scale:
  • The pH scale ranges from 0 to 14, where 7 is neutral, 7 is basic.
  • The pH is calculated as the negative logarithm of hydrogen ion concentration: pH = -log[H⁺].
• Strong Acids and Bases:
  • Strong acids completely dissociate in water (e.g., HCl, HNO₃).
  • Strong bases also dissociate completely (e.g., NaOH, KOH).
• Hydrolysis of Salts:
  • Salts formed from strong acids and strong bases do not hydrolyze, resulting in a neutral solution.
  • However, salts formed from weak acids or bases may hydrolyze, affecting the pH.
• Temperature Dependence:
  • The pH of pure water and neutral solutions is exactly 7 at 25°C.
  • As temperature increases, the pH of water decreases slightly due to increased ionization, but it remains neutral.