Assertion (A): Potassium is a stronger reducing agent than sodium.
Reason (R ): IE of potassium is less than that of sodium.

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.

Answer

To solve the question regarding the assertion and reason about potassium and sodium, we can break it down into clear steps:

### Step 1: Understand the Assertion and Reason
- **Assertion (A)**: Potassium is a stronger reducing agent than sodium.
- **Reason (R)**: Ionization energy (IE) of potassium is less than that of sodium.

### Step 2: Analyze the Ionization Energy Trend in Alkali Metals
- Alkali metals (Group 1) have a trend where ionization energy decreases as you move down the group. This is because:
- As you go down the group, the atomic size increases due to the addition of electron shells.
- The increased distance between the nucleus and the outermost electron reduces the effective nuclear charge experienced by that electron.

### Step 3: Compare the Ionization Energies of Sodium and Potassium
- Sodium (Na) has a higher ionization energy than potassium (K) because sodium is smaller in size compared to potassium.
- Therefore, it requires more energy to remove the outermost electron from sodium than from potassium.

### Step 4: Relate Ionization Energy to Reducing Ability
- A lower ionization energy means that an element can lose its outermost electron more easily.
- Since potassium has a lower ionization energy, it can be oxidized more readily than sodium, making it a stronger reducing agent.

### Step 5: Conclusion
- The assertion that potassium is a stronger reducing agent than sodium is true.
- The reason that the ionization energy of potassium is less than that of sodium is also true and explains why potassium is a stronger reducing agent.
- Therefore, both the assertion and reason are correct, and the reason correctly explains the assertion.

### Final Answer
Both the assertion and reason are correct, and R is the correct explanation of A.

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