4 replies to this topic

[Ayok]

Does anyone know about solubility of Fe(OH)3 in hot water? Is Fe(OH)3 precipitate faster or lower than in cold? Does someone have  graphic or diagram about solubility of Fe(OH)3 vs temperature? I unable to find in my book and internet. Please help me. Thanks for anyone helping

[PingPong]

Solubility of Fe(OH)3 depends on concentration of Fe³⁺ and concentration of OH^- and is determined by the Solubility Product K_sp of Fe(OH)₃

 

Use google to find Solubility Product at different temperatures.

[Ayok]

Ok, but is principle of Ksp work for solid? Because my Fe(OH)3 is in solid form, not in ionic form. Thanks for answering me pingpong

[PingPong]

It applies to all inorganics that are ions in solution, but can form solid precipitate if their Ksp is exceeded.

 

Ksp = [Fe³⁺]_*[OH^-]³

 

Ksp is an equilibrium constant (depending on temperature), which for Fe(OH)₃ is in the order of 10^-38 (exact number depends on which source you believe, use google) so you can imagine that the solubility of Fe(OH)₃ in water is very low.

 

You really must familiarise yourself with the theory of Solubility Product.

 

 

EDIT: Fe³⁺ and OH^- can also form various soluble complexes, each with their own equilibrium constant, which complicates calculating the exact solubility of Fe(OH)₃

See section in: http://chemwiki.ucda...lity_Equilibria

Edited by PingPong, 14 August 2014 - 05:45 AM.

[Ayok]

Ok, i get it Mr pingpong. Thanks