The concentration of iodide ions in a saturated solution of lead(II) iodide is _ M. The solubility product constant of PbI2 is 1.4 x 10⁻8.
a) 7.4 x 10⁻5 M
b) 2.8 x 10⁻4 M
c) 1.2 x 10⁻3 M
d) 5.6 x 10⁻3 M