Final answer:
The correct name for MgF2 is magnesium fluoride. The molar solubility can be determined using the Ksp value provided, leading to a calculation that factors in the dissociation of MgF2 into Mg2+ and F- ions in solution.
Step-by-step explanation:
The correct name for MgF2 is magnesium fluoride. It is an ionic compound consisting of magnesium cations (Mg2+) and fluoride anions (F-). To determine the molar solubility of magnesium fluoride from its solubility product (Ksp), we assume the solubility of MgF2 is represented by the variable s. When it dissolves, it dissociates according to the equation MgF2(s) → Mg2+(aq) + 2F-(aq), whereby one mole of MgF2 produces one mole of Mg2+ and two moles of F-.
Using the Ksp expression, Ksp = [Mg2+][F-]^2, and substituting s for [Mg2+] and 2s for [F-], we have Ksp = s(2s)^2 = 4s^3. Plugging in the given Ksp value, 6.4 × 10-9, we get 6.4 × 10-9 = 4s^3. Solving for s yields the molar solubility of magnesium fluoride.