Assertion : `CrO_(3)` reacts with HCl to form chromyl chloride gas
Reason : Chromyl chloride `(CrO_(2)Cl_(2))` has tetrahedral shape.

Options

A. If both assertion and reason are true and the reason is the correct explanation of assertion
B. If both assertion and reason are true and the reason is not the correct explanation of assertion
C. If assertion is false but reason is true
D. If assertion is true but the reason is false

Answer

To solve the question, we need to analyze the assertion and reason statements separately and then determine their truthfulness and relationship.

### Step 1: Analyze the Assertion
The assertion states that `CrO3` reacts with HCl to form chromyl chloride gas.

- **Chemical Reaction**: The reaction can be represented as:
\[ CrO_3 + 6HCl \rightarrow CrO_2Cl_2 + 3H_2O \]
- **Conclusion**: The assertion is true because chromium trioxide (`CrO3`) indeed reacts with hydrochloric acid (`HCl`) to produce chromyl chloride (`CrO2Cl2`) and water.

### Step 2: Analyze the Reason
The reason states that chromyl chloride `(CrO2Cl2)` has a tetrahedral shape.

- **Valence Electrons Calculation**:
- Chromium (Cr) has 6 valence electrons.
- There are 2 chlorine (Cl) atoms, each contributing 1 valence electron.
- Total = 6 (from Cr) + 2 (from Cl) = 8 valence electrons.

- **Hybridization**:
- Using the formula for determining hybridization:
\[ \text{Hybridization} = \frac{(\text{Number of valence electrons} + \text{Number of monovalent atoms})}{2} \]
- Here, we have:
\[ \text{Hybridization} = \frac{(6 + 2)}{2} = 4 \quad \text{(sp}^3\text{ hybridization)} \]

- **Shape Determination**:
- Since there are no lone pairs and 4 bond pairs (2 double bonds with O and 2 single bonds with Cl), the shape of `CrO2Cl2` is indeed tetrahedral.

- **Conclusion**: The reason is also true as chromyl chloride does have a tetrahedral shape.

### Step 3: Determine the Relationship
Now we need to determine if the reason explains the assertion.

- The assertion is about the reaction between `CrO3` and `HCl`, while the reason discusses the shape of chromyl chloride. Although both statements are true, the reason does not explain why `CrO3` reacts with `HCl` to form chromyl chloride.

### Final Conclusion
Both the assertion and reason are true, but the reason does not provide a correct explanation for the assertion. Therefore, the correct answer is:

**Answer: 2** - Both assertion and reason are true, but the reason is not the correct explanation of the assertion.

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