Fe(OH)3(a) IAP

[pia said]

Hi, i'm confused with the Fe(OH)3(a) IAP, the reaction is Fe(OH)3 + 3H+ = Fe+3 + 3H2O so: do the IAP is {Fe+3}/{H+}^3 ?

[dlparkhurst]

For that reaction, yes:

IAP = {Fe+3}{H2O}^3/{H+}^3

but {H2O} is usually close to 1.

You can write the reaction

Fe(OH)3 = Fe+3 + 3OH-

IAP will be different, but the log K will be different.

[pia said]

thanks!!