Which of the following are Lewis acids?

Options

A. `(CH_(3))_(3)B`
B. `CH_(2)`
C. S
D. `CH_(3)`

Answer

To determine which of the given options are Lewis acids, we need to understand the definition of a Lewis acid. A Lewis acid is a substance that can accept a pair of electrons to form a covalent bond. This typically means that the Lewis acid must have an empty orbital available to accept these electrons.

### Step-by-Step Solution:

1. **Identify the Definition of Lewis Acids:**
- A Lewis acid is defined as a species that can accept an electron pair. This usually requires the presence of an empty orbital.

2. **Analyze Each Compound:**
- We need to examine each of the given compounds to see if they have an empty orbital.

3. **Evaluate CH₃B(OH)₂:**
- CH₃B(OH)₂ (trimethyl borate) is a Lewis acid because boron (B) has an empty p-orbital and can accept a pair of electrons. Boron is typically electron-deficient and can form bonds by accepting electron pairs.

4. **Evaluate Other Compounds:**
- For other compounds, we need to check if they have empty orbitals:
- If a compound is a simple element or does not have an empty orbital, it cannot be classified as a Lewis acid.
- For example, CH₃ (methyl group) does not have an empty orbital and is not a Lewis acid.

5. **Conclusion:**
- The only compound that qualifies as a Lewis acid from the given options is CH₃B(OH)₂.

### Final Answer:
The only Lewis acid among the given options is CH₃B(OH)₂.

---