Give the expression for the solubility product constant for baf2.

Solubility product constant (Ksp) is applied to the saturated ionic solutions which are in equilibrium with its solid form. The solid is partially dissociated into its ions.

For the BaF, the dissociation as follows;
BaF₂(s) ⇄ Ba²⁺(aq) + 2F⁻(aq)

Hence,
        Ksp = [Ba²⁺(aq)] [F⁻(aq)]²

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.