Assertion (A) : After white washing the walls, a shiny white finish on walls is obtained after two to three days.
Reason (R ) : Calcium Oxide reacts with Carbon dioxide to form Calcium Hydrogen Carbonate which gives shiny white finish.

Options

A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is NOT the correct explanation of A.
C. A is true but R is false.
D. A is false and R is True.

Explanation

To solve the given question, we will analyze the assertion and the reason provided, and determine their validity.

### Step 1: Analyze the Assertion
The assertion states: "After whitewashing the walls, a shiny white finish on walls is obtained after two to three days."
- This statement is **true**. When walls are whitewashed, they do appear shiny and white after the application, and this finish typically becomes more pronounced after a couple of days as the materials settle and dry.

### Step 2: Analyze the Reason
The reason states: "Calcium Oxide reacts with Carbon dioxide to form Calcium Hydrogen Carbonate which gives shiny white finish."
- This statement is **false**. The correct reaction involves Calcium Oxide (CaO) reacting with water (H2O) to form Calcium Hydroxide (Ca(OH)₂), which contributes to the shiny finish. Calcium Oxide does not react with Carbon Dioxide to produce Calcium Hydrogen Carbonate in the context of whitewashing.

### Step 3: Conclusion
- Since the assertion is true and the reason is false, we can conclude that the correct answer is that the assertion is true but the reason is false.

### Final Answer
The correct option is: **Assertion is true but reason is false.**

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