Ksp Expression

Solubility product for sparingly soluble salt.

solubility-precipitationReviewed 21/8/2026
On this page
  1. Equation
  2. Variables
  3. Conditions
  4. Example
  5. Common errors
  6. Sources

Equation and purpose

Solubility product for sparingly soluble salt.

Ksp Expression
\[K_{sp}=[A^+]^a[B^-]^b\]

Solubility product for sparingly soluble salt.

REARRANGEMENTS
$s = (Ksp/(a^a b^b))^{1/(a+b)}$ for simple stoich.

Dimensional check: M^{a+b} ✓

Variables and units

VARIABLES
SymbolQuantityUnitNotes
KspKsp
[ion][ion]

Conditions and limitations

Pure solid omitted; at saturation.

Worked example

AgCl: Ksp=[Ag+][Cl−].

Ksp Expression

Solubility product for sparingly soluble salt.

Equation

Ksp=[A+]a[B]bK_{sp}=[A^+]^a[B^-]^b

Inline: $K_{sp}=[A^+]^a[B^-]^b$$

Variables

SymbolQuantityUnitNotes
KspKspsolubility product
[ion][ion]ion concentrationM

Conditions and limitations

Pure solid omitted; at saturation.

Rearrangements

s=(Ksp/(aabb))1/(a+b)s = (Ksp/(a^a b^b))^{1/(a+b)} for simple stoich.

Dimensional check: M^{a+b} ✓

Worked example

AgCl: Ksp=[Ag+][Cl−].

Steps: write equation → substitute with units → check dimensional consistency → report with correct significant figures.

Common errors

  • Including solid in expression

Sources

  • NIST Physical Constants 2022 — CODATA.

Reviewed 2026-08-21 by Editorial Team; due 2027-08-21.

Common errors

  • Including solid in expression
C
Chemistry Fundamentals Editorial TeamAuthor
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Editorial Review BoardReviewer

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Reviewed August 21, 2026

SOURCES

  1. [nist-2022]NIST Physical Constants 2022 (2022). NISThttps://physics.nist.gov/constants
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Sources · Corrections

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