A: `Cr_(2)O_(7)^(2-)`becomes equilibrium with `CrO_(4)^(2-)` at PH > 5
R: `Cr_(2)O_(7)^(2-)` is tetrahedral having `Cr -O- Cr angle109^(@)28`

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

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

### Step 1: Analyze the Assertion
The assertion states that \( \text{Cr}_2\text{O}_7^{2-} \) becomes equilibrium with \( \text{CrO}_4^{2-} \) at pH > 5.

- **Understanding the Chemistry**: The equilibrium between dichromate (\( \text{Cr}_2\text{O}_7^{2-} \)) and chromate (\( \text{CrO}_4^{2-} \)) occurs in aqueous solutions. The equilibrium can be represented as:
\[ \text{Cr}_2\text{O}_7^{2-} + 2 \text{OH}^- \rightleftharpoons 2 \text{CrO}_4^{2-} + \text{H}_2\text{O} \]
- **pH Consideration**: This equilibrium is favored at higher pH values, specifically above pH 4. However, the assertion claims that it occurs at pH > 5, which is not accurate. The equilibrium does shift towards chromate at pH values above 4, but the assertion is misleading as it implies a more restrictive condition.

### Conclusion for Assertion
The assertion is **false** because the equilibrium between \( \text{Cr}_2\text{O}_7^{2-} \) and \( \text{CrO}_4^{2-} \) occurs at pH = 4, not strictly above 5.

### Step 2: Analyze the Reason
The reason states that \( \text{Cr}_2\text{O}_7^{2-} \) is tetrahedral with a \( \text{Cr-O-Cr} \) angle of 109.28°.

- **Structure of \( \text{Cr}_2\text{O}_7^{2-} \)**: The structure of dichromate ion is not tetrahedral. Instead, it has a more complex structure where the chromium atoms are connected by bridging oxygen atoms.
- **Bond Angle**: The actual bond angle in \( \text{Cr}_2\text{O}_7^{2-} \) is approximately 126°, not 109.28° as stated in the reason.

### Conclusion for Reason
The reason is also **false** because \( \text{Cr}_2\text{O}_7^{2-} \) does not have a tetrahedral geometry, and the bond angle is not 109.28°.

### Final Conclusion
Both the assertion and the reason are incorrect. Therefore, the correct answer is that both statements are false.