Assertion (A) : Aluminum is passive towares conc ` HNO_3`
Reason (R) : Due to formation of layer of nitrate on aluminium

Options

A. If both (A) and (R) are correct and (R) is correct explanation of (A)
B. If both (A) and (R) are correct and (R) is not 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 about aluminum's behavior towards concentrated nitric acid (HNO3), we can break it down step by step:

### Step 1: Understand the Assertion
The assertion states that "Aluminum is passive towards concentrated HNO3." This means that aluminum does not react with concentrated nitric acid under normal conditions.

**Hint:** Consider what "passive" means in a chemical context.

### Step 2: Analyze the Reason
The reason provided is "Due to the formation of a layer of nitrate on aluminum." We need to evaluate whether this reason accurately explains the assertion.

**Hint:** Think about what actually happens when aluminum comes into contact with concentrated nitric acid.

### Step 3: Identify the Actual Reaction
When aluminum is exposed to concentrated nitric acid, it forms a protective layer of aluminum oxide (Al2O3) on its surface. This oxide layer prevents further reaction between aluminum and the acid, making aluminum passive.

**Hint:** Recall the properties of aluminum and its oxides.

### Step 4: Compare the Reason with the Assertion
The assertion is true because aluminum does become passive due to the formation of a protective layer. However, the reason is incorrect because it states that the layer formed is a "layer of nitrate," which is not accurate. The correct layer is aluminum oxide (Al2O3), not a nitrate.

**Hint:** Focus on the specific compounds involved in the reaction.

### Step 5: Conclusion
Based on the analysis:
- The assertion is true: Aluminum is indeed passive towards concentrated HNO3.
- The reason is false: The layer formed is aluminum oxide, not a layer of nitrate.

Thus, the correct conclusion is that the assertion is true, but the reason is false.

### Final Answer
The correct option is that the assertion is true, but the reason is false.

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