Question

Which of the following ions would have the largest hydration sphere?

a) Na⁺
b) K⁺
c) Cl⁻
d) Mg²⁺

Answer 1

The Mg²⁺ ion has the largest hydration sphere due to its smaller size and higher charge compared to Na⁺, K⁺, and Cl− ions, resulting in a stronger attraction to water molecules.

Step-by-step explanation:

The ion that would have the largest hydration sphere is Mg2+. In the hydration process, water molecules surround the ions, and the extent of hydration depends on the charge and size of the ion. The smaller and more highly charged the ion, the larger the hydration sphere it can attract. Magnesium ion (Mg2+) is smaller and has a higher charge than sodium (Na+), potassium (K+), and chloride (Cl−) ions. Therefore, Mg2+ has a much stronger attraction to the water molecules, leading to a larger hydration sphere.