Consider the following species and find out total number of species which are polar and can act as Lewis acid
`C Cl_(4),CO_(2),SO_(2),AlCl_(3),HCHO,SO_(3),SiCl_(4),BCl_(3),CF_(4)`

Explanation

To determine the total number of species that are polar and can act as Lewis acids from the given list, we will analyze each compound step by step.

### Step 1: Analyze the species

1. **CCl₄ (Carbon Tetrachloride)**:
- Structure: Tetrahedral
- Hybridization: sp³
- Polarity: Non-polar (dipole moment = 0)

2. **CO₂ (Carbon Dioxide)**:
- Structure: Linear
- Hybridization: sp
- Polarity: Non-polar (dipole moment = 0)

3. **SO₂ (Sulfur Dioxide)**:
- Structure: Bent
- Hybridization: sp²
- Polarity: Polar (dipole moment ≠ 0)
- Lewis Acid: Yes, can accept electrons due to vacant d-orbitals.

4. **AlCl₃ (Aluminum Chloride)**:
- Structure: Trigonal planar
- Hybridization: sp²
- Polarity: Non-polar (dipole moment = 0)
- Lewis Acid: Yes, can accept electrons.

5. **HCHO (Formaldehyde)**:
- Structure: Trigonal planar around carbon
- Hybridization: sp²
- Polarity: Polar (due to the C=O bond)
- Lewis Acid: Yes, can accept electrons.

6. **SO₃ (Sulfur Trioxide)**:
- Structure: Trigonal planar
- Hybridization: sp²
- Polarity: Non-polar (dipole moment = 0)

7. **SiCl₄ (Silicon Tetrachloride)**:
- Structure: Tetrahedral
- Hybridization: sp³
- Polarity: Non-polar (dipole moment = 0)

8. **BCl₃ (Boron Trichloride)**:
- Structure: Trigonal planar
- Hybridization: sp²
- Polarity: Non-polar (dipole moment = 0)

9. **CF₄ (Carbon Tetrafluoride)**:
- Structure: Tetrahedral
- Hybridization: sp³
- Polarity: Non-polar (dipole moment = 0)

### Step 2: Identify polar species that can act as Lewis acids

From the analysis:
- **Polar species**: SO₂ and HCHO
- **Lewis acids**: SO₂ and HCHO

### Conclusion

The total number of species that are polar and can act as Lewis acids is **2** (SO₂ and HCHO).

### Final Answer
**Total number of polar species that can act as Lewis acids: 2**

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