Which of the following ions has the maximum hydration energy?

Options

A. `Al^(3+)`
B. `Li^(+)`
C. `Cr^(3+)`
D. `Ca^(2+)`

Explanation

To determine which ion has the maximum hydration energy, we can follow these steps:

### Step 1: Understand Hydration Energy
Hydration energy is the energy released when ions are surrounded by water molecules. It is influenced by the charge of the ion and its size. Higher charges typically lead to greater hydration energy.

**Hint:** Remember that hydration energy increases with the charge of the ion.

### Step 2: Analyze the Given Ions
Let's consider the ions provided in the question. We need to evaluate their charges and solubility in water. Common ions that might be considered include Al³⁺ and Cr³⁺.

**Hint:** List the charges of the ions you are comparing.

### Step 3: Compare the Charges
Both Al³⁺ and Cr³⁺ have a charge of +3. However, we need to consider their solubility in water as well.

**Hint:** If two ions have the same charge, their solubility can affect their hydration energy.

### Step 4: Check Solubility
Al³⁺ is known to be soluble in water, while Cr³⁺ has limited solubility. Since hydration energy is relevant only for ions that can dissolve in water, we focus on Al³⁺.

**Hint:** Solubility is crucial for determining which ion can exhibit hydration energy.

### Step 5: Conclusion
Since Al³⁺ is soluble in water and has a high charge, it will have the maximum hydration energy among the ions considered. Cr³⁺, despite having the same charge, does not contribute to hydration energy due to its low solubility.

**Final Answer:** Al³⁺ has the maximum hydration energy.