At what conc. of the Ba2+ ions would BaSO4 start precipitating from a solution in which the concentration of the Ba2+ ions is 0.0010M(Ksp of BaSO4 is 10^-10)

Dear Student,

We have to find the concentration of Ba²⁺ ions at which BaSO₄  would start precipitating.
So, assuming that the concentration mentioned by you is of SO₄^2- ions, and not Ba²⁺ ions,
we can find use the solubility product to get the concentration of Ba²⁺ ions.

$$\begin{gathered} K_{sp}=\left[B{a}^{2+}\right]\left[S{O_4}^{2-}\right] \\ {10}^{-10}=\left[B{a}^{2+}\right]\left[0.001\right] \\ \left[B{a}^{2+}\right]=\frac{{10}^{-10}}{{10}^{-3}}={10}^{-7} M \end{gathered}$$

Hope it helps.

Regards