Which of the following has the highest solubility product?

Options

A. (A) KOH
B. (A) CsOH
C. (C) LiOH
D. (D) RbOH

Answer

To determine which of the given compounds has the highest solubility product, we need to analyze the solubility of the alkali metal hydroxides mentioned in the options. Here’s a step-by-step solution:

### Step 1: Identify the Compounds
The question mentions alkali metal hydroxides. Let's identify the common alkali metal hydroxides:
- Lithium hydroxide (LiOH)
- Sodium hydroxide (NaOH)
- Potassium hydroxide (KOH)
- Rubidium hydroxide (RbOH)
- Cesium hydroxide (CsOH)

### Step 2: Understand Solubility Product (Ksp)
The solubility product (Ksp) is a constant that indicates the solubility of a compound in water. A higher Ksp value means a higher solubility of the compound in water.

### Step 3: Analyze the Trend in Solubility
In alkali metal hydroxides, the solubility generally increases as we move down the group from lithium to cesium. This is due to the following reasons:
- As the size of the alkali metal ion increases, the lattice energy decreases, making it easier for the compound to dissolve.
- The ionic character of the hydroxides increases, leading to better solubility in water.

### Step 4: Compare the Solubility of Each Hydroxide
- **LiOH**: Lower solubility
- **NaOH**: Moderate solubility
- **KOH**: Higher solubility
- **RbOH**: Even higher solubility
- **CsOH**: Highest solubility

### Step 5: Conclusion
Based on the trend, cesium hydroxide (CsOH) has the highest solubility product among the alkali metal hydroxides listed.

### Final Answer
**Cesium hydroxide (CsOH) has the highest solubility product.**

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