Predict which member of each pair produces the more acidic aqueous solution: (a) K+ or Cu2+ (b) Fe2+ or Fe3+ (c) Al3+ or Ga3+.

Verified step by step guidance

1. Step 1: Understand the concept of acidity in aqueous solutions. Acidity in aqueous solutions is often related to the ability of a cation to polarize water molecules, leading to the release of protons (H+). This is influenced by the charge density of the cation.
2. Step 2: Analyze the charge and size of the cations. Higher charge and smaller ionic radius generally increase the charge density, making the cation more effective at polarizing water molecules and thus more acidic.
3. Step 3: Compare the cations in each pair based on their charge and size. For example, between K+ and Cu2+, Cu2+ has a higher charge and likely a smaller radius, making it more acidic.
4. Step 4: Apply the same analysis to the other pairs. For Fe2+ vs. Fe3+, Fe3+ has a higher charge, and for Al3+ vs. Ga3+, consider the periodic trends and charge density.
5. Step 5: Conclude which cation in each pair is more acidic based on the analysis of charge density and polarization ability.