Which solution contains the biggest amount, in mol, of chloride ions? A. 20 cm3 of 0.50 mol dm−3 NH4Cl B. 60 cm3 of 0.20 mol dm−3 MgCl2 C. 70 cm3 of 0.30 mol dm−3 NaCl D. 100 cm3 of 0.30 mol dm−3 ClCH2COOH