Tooth enamel is composed of hydroxyapatite, whose simplest formula is Ca₅(PO₄)₃OH, and whose corresponding Ksp = 6.8 × 10^-27.As discussed in the “Chemistry and Life” box on page 730, fluoride in fluorinated water or in toothpaste reacts with hydroxyapatite to form fluoroapatite,

Ca₅(PO₄)₃F,whose Ksp = 1.0 × 10^-60.

a)Write the expression for the solubility-constant for hydroxyapatite and for fluoroapatite.

(b) Calculate the molar solubility of each of these compounds.