MgCl2(aq) is an ionic compound which will have the releasing of 2 Cl⁻ ions ions in water for every molecule of MgCl2 that dissolves. MgCl2(s) --> Mg+(aq) + 2 Cl⁻(aq) [Cl⁻] = 0.098 mol MgCl2/1L × 2 mol Cl⁻ / 1 mol MgCl2 = 0.20 M The answer to this question is [Cl⁻] = 0.20 M
