Question

if ph of saturated solution of fe(oh)3 in water is 10 then ksp of fe(oh)3 will be​

Answer 1

Given:

• The pH of a saturated solution of Fe(OH)₃ in water is equal to 10.
• pKw of water at room temperature is 14.

To find:

The Ksp of Fe(OH)₃.

Solution:

• Each mole of Fe(OH)₃ dissociates to give one mole of Fe³⁺ ion and three moles of OH⁻ ion. Hence, [Fe³⁺] = [OH⁻]/3.
• pOH of the solution is equal to pKw - pH = 14 - 10 = 4.Hence, [OH⁻] = 10⁻⁴

• Since,  [Fe³⁺] = [OH⁻]/3 ⇒ [Fe³⁺] = 10⁻⁴/3
• Ksp = [Fe³⁺].[OH⁻]³ = (10⁻⁴/3).(10⁻⁴)³ = 3.33*10⁻¹⁷

Answer:

The Ksp of Fe(OH)₃ is equal to 3.33*10⁻¹⁷

Answer 2

Ksp of Fe(OH)₃ is 3.33 × 10⁻¹⁷

Explanation:

The dissociation of Fe(OH)₃ is given as:

Fe(OH)₃ → Fe³⁺ + 3OH⁻

For any aqueous solution:

pH + pOH = 14

Where,

pH = 10 (given)

Now, the equation becomes,

10 + pOH = 14

pOH = 14 - 10

∴ pOH = 4

[OH⁻] = $10^{-pOH}$

∴ [OH⁻] = 10⁻⁴

The solubility equilibrium is given by the formula:

Ksp = [Fe³⁺].[OH⁻]³

For the given reaction, we get,

[Fe³⁺] = [OH⁻]/3

On substituting the values, we get,

[Fe³⁺] = 10⁻⁴/3

Now, the solubility equilibrium formula becomes,

Ksp = 10⁻⁴/3 × (10⁻⁴)³

Ksp = 10⁻⁴/3 × 10⁻¹²

Ksp = 10⁻¹⁶/3

∴ Ksp = 3.33 × 10⁻¹⁷