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 analyze the given question, we need to evaluate both the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
The assertion states that CrO₃ (chromium trioxide) reacts with HCl to form chromyl chloride gas (CrO₂Cl₂).
- **Chemical Reaction**: The balanced reaction can be written as:
\[ CrO_3 + 6HCl \rightarrow CrO_2Cl_2 + 2Cl_2 + 3H_2O \]
- This reaction is indeed correct, as CrO₃ reacts with HCl to produce chromyl chloride gas.

2. **Understanding the Reason**:
The reason states that chromyl chloride (CrO₂Cl₂) has a tetrahedral shape.
- **Molecular Geometry**: To determine the shape of CrO₂Cl₂, we need to analyze the hybridization and steric number.
- The central atom, chromium (Cr), has 6 valence electrons (4 from 3d and 2 from 4s). In CrO₂Cl₂:
- There are 2 double bonds with oxygen and 2 single bonds with chlorine.
- This gives a total of 4 sigma bonds and no lone pairs on the chromium atom.
- **Steric Number Calculation**: The steric number is calculated as the number of sigma bonds plus lone pairs. Here, it is:
\[ \text{Steric Number} = 4 \text{ (from 4 bonds)} + 0 \text{ (lone pairs)} = 4 \]
- **Hybridization**: With a steric number of 4, the hybridization is sp³, which corresponds to a tetrahedral geometry.

3. **Conclusion**:
- The assertion is **true** because CrO₃ does react with HCl to form chromyl chloride gas.
- The reason is **false** because, although CrO₂Cl₂ has a tetrahedral shape, the assertion does not depend on the shape of the molecule; thus, the reason does not adequately support the assertion.

### Final Answer:
- The assertion is true, but the reason is false. Therefore, the correct option is that both statements are true, but the reason does not correctly explain the assertion.