# Is an iron (II) sulphate solution supposed to turn cloudy when silver nitrate is added?

$\ce{AgNO3}$ is not suppose to cause a precipitation when mixed with $\ce{FeSO4}$, but the acidified solution turns slightly cloudy when $\ce{AgNO3}$ is added.

Is this suppose to happen? solutions are all prepared fresh. Any reason as to why? This also happens when silver nitrate is added to magnesium sulphate.

Picture is as attached, the left one has the $\ce{AgNO3}$ added (labelled Ag) while the one on the right has $\ce{Ba(NO3)2}$ added to show the comparison

• photo added. any clue as to why this happened? chemicals are also newly bought. expiring in 2016, only been on the shelf for less than 3 months. – user15862 Apr 28 '15 at 5:48

According to this resource for solubility rules, $\ce{BaSO4}$ is insoluble and $\ce{Ag2SO4}$ is slightly insoluble, which would explain the the cloudiness of each solution, as well as why the $\ce{BaSO4}$ solution is cloudier than the $\ce{Ag2SO4}$ solution.
According to this table, $\ce{BaSO4}$ has a $K_{\mathrm{sp}}$ of $1.1 \times 10^{-10}$. Comparably, $\ce{Ag2SO4}$ has a $K_\mathrm{sp}$ of $1.2 \times 10^{-5}$, which is considerably higher than $\ce{BaSO4}$.
If you are not aware the $K_{\mathrm{sp}}$ is a mathematical measurement describing the solubility of a salt at a certain temperature (usually $25^{\mathrm{o}} \mathrm{C}$), and is found by multiplying the concentration of the salt's dissolved ions, each raised to the power of their respective stoichiometric coefficients. The higher the $K_{\mathrm{sp}}$, the more soluble a salt is. For example, the $K_{\mathrm{sp}}$ for $\ce{Ag2SO4}$ would be given by the expression: $K_{\mathrm{sp}}=[\ce{Ag+}]^2\cdot[\ce{SO4^{2-}}]$.