Arrange the following cations in the increasing order their enthalpy of hydration: K⁺,Ca²⁺,and Mg²⁺. A) K⁺

Question

Arrange the following cations in the increasing order their enthalpy of hydration: K⁺,Ca²⁺,and Mg²⁺. A) K⁺ < Ca²⁺ < Mg²⁺ B) Mg²⁺ < Ca²⁺ < K⁺ C) Ca²⁺ < K⁺ < Mg²⁺ D) Ca²⁺ < Mg²⁺ < K⁺ E) Mg²⁺ < K⁺ < Ca²⁺

Quizplus · Accepted Answer

The enthalpy of hydration depends on the charge density of the ion. Higher charge and smaller size lead to a higher enthalpy of hydration. Mg^2+ has a higher charge and smaller size compared to Ca^2+, and K^+ has the lowest charge density among them. Therefore, K^+ < Ca^2+ < Mg^2+.

Arrange the Following Cations in the Increasing Order Their Enthalpy