Question

Ph of which salt is same for 1m and 5m solution both and why?



a.Hcoona



b.C6h5nh3^+cl



c.Nh4cn



d. Nacn

Answer 1

pH of NH₄CN is same for both 1 M and 5 M solutions.

• NH₄CN is a salt containing weak acidic radical(CN-) and weak basic radical(NH4+).
• pH of salts containing weak acidic as well as weak basic radicals does not depend on the concentration of the salt.
• The formula for the pH is equal to (pKw + pKa - pKb)/2
• Since the above formula is independent of concentration the pH of 1 M and 5 M NH₄CN  solutions are same.