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 species step by step.

### Step 1: Analyze each species for polarity
1. **CCl₄ (Carbon Tetrachloride)**:
- Structure: Tetrahedral
- Dipole moment: The dipoles from the C-Cl bonds cancel out.
- **Result**: Non-polar

2. **CO₂ (Carbon Dioxide)**:
- Structure: Linear
- Dipole moment: The dipoles from the C=O bonds cancel out.
- **Result**: Non-polar

3. **SO₂ (Sulfur Dioxide)**:
- Structure: Bent
- Dipole moment: The dipoles do not cancel due to the bent shape.
- **Result**: Polar

4. **AlCl₃ (Aluminum Chloride)**:
- Structure: Trigonal planar
- Dipole moment: The dipoles from the Al-Cl bonds cancel out.
- **Result**: Non-polar

5. **HCHO (Formaldehyde)**:
- Structure: Trigonal planar
- Dipole moment: The dipole from the C=O bond does not cancel with the H-C bond.
- **Result**: Polar

6. **SO₃ (Sulfur Trioxide)**:
- Structure: Trigonal planar
- Dipole moment: The dipoles from the S=O bonds cancel out.
- **Result**: Non-polar

7. **SiCl₄ (Silicon Tetrachloride)**:
- Structure: Tetrahedral
- Dipole moment: The dipoles from the Si-Cl bonds cancel out.
- **Result**: Non-polar

8. **BCl₃ (Boron Trichloride)**:
- Structure: Trigonal planar
- Dipole moment: The dipoles from the B-Cl bonds cancel out.
- **Result**: Non-polar

9. **CF₄ (Carbon Tetrafluoride)**:
- Structure: Tetrahedral
- Dipole moment: The dipoles from the C-F bonds cancel out.
- **Result**: Non-polar

### Summary of Polarity:
- Polar species: SO₂, HCHO
- Non-polar species: CCl₄, CO₂, AlCl₃, SO₃, SiCl₄, BCl₃, CF₄

### Step 2: Analyze each polar species for Lewis acidity
1. **SO₂**:
- Electron deficiency: Sulfur can expand its octet and accept electrons.
- **Result**: Acts as a Lewis acid.

2. **HCHO**:
- Electron deficiency: The carbon atom has a partial positive charge, making it electron deficient.
- **Result**: Acts as a Lewis acid.

### Final Count:
- Total polar species that can act as Lewis acids: **2 (SO₂ and HCHO)**

### Conclusion:
The total number of species which are polar and can act as Lewis acids is **2**.

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