Salt Hydrolysis pH Calculator
Why a dissolved salt is rarely neutral.
Work out Salt Hydrolysis pH. Why a dissolved salt is rarely neutral. Names the sign error before you make it.
Ka of the weak parent acid, or Kb of the weak parent base. Acetic acid and ammonia are both 1.8e-5.
pH of the salt solution
8.87
Basic — the anion pulls a proton off water
A dissolved salt is not automatically neutral. Sodium acetate gives a pH near 9 because acetate is a base strong enough to take a proton from water; ammonium chloride gives about 5 because ammonium gives one up. Only a salt of a strong acid AND a strong base, such as sodium chloride, is genuinely neutral. The hydrolysis constant is Kw divided by the parent's constant, which is why a weaker parent acid produces a more basic salt — the conjugate relationship again. This uses the standard approximation that the extent of hydrolysis is small compared with the salt concentration. It holds comfortably for the concentrations and constants used in teaching labs, and starts to drift for very dilute solutions of very weak parents.
How the Salt Hydrolysis pH Calculator works
Enter the salt concentration and its weak parent's Ka or Kb to get the pH. Sodium acetate lands near 9 and ammonium chloride near 5 — only a salt of a strong acid and a strong base, like sodium chloride, is genuinely neutral.
Also known as: ph of a salt solution calculator · is a salt acidic or basic · ph of sodium acetate · hydrolysis constant calculator
Frequently asked questions
Are all salts neutral in water?
No. Only salts of a strong acid and a strong base are. If either parent is weak, its ion reacts with water and shifts the pH — acetate makes the solution basic, ammonium makes it acidic.
What is the pH of 0.1 M sodium acetate?
About 8.87. Acetate is the conjugate base of a weak acid, so it takes protons from water, generating hydroxide.
What is the hydrolysis constant?
Kh = Kw ÷ the parent's constant. A weaker parent acid gives a larger Kh and a more basic salt, which is the conjugate relationship applied to hydrolysis.
What about a salt where both parents are weak?
Then the pH depends on which is weaker, and the calculation needs both constants together. Ammonium acetate happens to come out near neutral because Ka and Kb are nearly equal — a coincidence, not a rule.
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