The concentration of Ag+ ions is 1x10^-6 M in AgBr solution. Find minimum concentration of Br- ions necessary to cause precipitation of AgBr. ( Ksp of AgBr= 4x10^-13 M^2)?

1 Answer
May 7, 2017

We interrogate the equilibrium reaction:

Ag++BrAgBr(s)

Explanation:

We have been given the thermodynamic equilibrium constant for this reaction, i.e.:

Ksp=[Ag+][Br]=4×1013.

Ksp is the so-called solubility product, which have been measured for a host of inorganic salts. And so we simply substitute in [Ag+], and solve for [Br]............

[Br]=Ksp[Ag+]=4×10131×106=4.0×107molL1

And thus, should [Ag+]>4.0×107molL1, a precipitate of creamy yellow AgBr salt will be observed.