Assertion (A): NaOH is a stronger base than KOH.
Reason (R ): KOH is more soluble in water than NaOH.

Options

A. If both (A) and (R ) are correct and (R ) is the correct explanation of (A).
B. If both (A) and (R ) are correct, but (R ) is not the correct explanation of (A).
C. If (A) is correct, but (R ) is incorrect.
D. If (A) is incorrect, but (R ) is correct.

Explanation

To solve the question regarding the assertion and reason, we will analyze both statements step by step.

### Step 1: Analyze the Assertion (A)
The assertion states that "NaOH is a stronger base than KOH." To evaluate this, we need to consider the properties of sodium hydroxide (NaOH) and potassium hydroxide (KOH).

- **Basicity of Alkali Metal Hydroxides**: In the alkali metal group, the basicity of hydroxides increases as we move down the group. This is due to the decrease in ionization enthalpy and an increase in electropositivity of the metals. Therefore, KOH, being from a lower period than NaOH, is actually a stronger base.

**Conclusion for Assertion**: The assertion is **false**.

### Step 2: Analyze the Reason (R)
The reason states that "KOH is more soluble in water than NaOH." We need to evaluate the solubility of both compounds.

- **Solubility in Water**: Potassium hydroxide (KOH) is indeed more soluble in water compared to sodium hydroxide (NaOH). This higher solubility allows KOH to dissociate more readily in aqueous solutions, contributing to its stronger basic nature.

**Conclusion for Reason**: The reason is **true**.

### Step 3: Final Evaluation
Since the assertion is false and the reason is true, we can conclude that the correct answer to the question is that the assertion is incorrect while the reason is correct.

### Final Answer
The correct answer is: **D** (Assertion is false, Reason is true).

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