Which between Ca²⁺ and Li⁺ is the harder Lewis acid? Justify your answer.

• A. The harder acid is Li⁺ because it is more stable due to its larger size giving it a greater tendency to accept electrons.
• B. The harder acid is Li⁺ because it is less stable due to its larger size giving it a greater tendency to donate electrons. 
• C. The harder acid is Li⁺ because it is less stable due to its smaller size giving it a greater tendency to accept electrons.
• D. The harder acid is Li⁺ because it is more stable due to its smaller size giving it a greater tendency to donate electrons.

Answer: (C)