Which of the following compounds produces the greatest number of moles of ions per mole of formula units when dissolved in water?

• A. NaCl
• B. AlCl3
• C. K2SO4
• D. CaCl2

Answer: (B)

Verified step by step guidance

1. Identify the ions produced by each compound when it dissolves in water by writing their dissociation equations.
2. For NaCl, the dissociation is: \(\mathrm{NaCl (s) \rightarrow Na^{+} (aq) + Cl^{-} (aq)}\), producing 2 moles of ions per mole of NaCl.
3. For AlCl3, the dissociation is: \(\mathrm{AlCl_3 (s) \rightarrow Al^{3+} (aq) + 3Cl^{-} (aq)}\), producing 4 moles of ions per mole of AlCl3.
4. For K2SO4, the dissociation is: \(\mathrm{K_2SO_4 (s) \rightarrow 2K^{+} (aq) + SO_4^{2-} (aq)}\), producing 3 moles of ions per mole of K2SO4.
5. For CaCl2, the dissociation is: \(\mathrm{CaCl_2 (s) \rightarrow Ca^{2+} (aq) + 2Cl^{-} (aq)}\), producing 3 moles of ions per mole of CaCl2. Compare the total moles of ions from each compound to determine which produces the greatest number.