Which of the following is the strongest nucleophile?

Options

A. `OH^(-)`
B. `CH_(3)OH`
C. `CH_(3)S^(-)`
D. `CH_(3)O^(-)`

Explanation

To determine the strongest nucleophile among the given options, we need to analyze the nucleophilicity of each species based on their structure and the presence of negative charges. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand Nucleophilicity
Nucleophilicity refers to the ability of a species to donate an electron pair to an electrophile. Generally, a stronger nucleophile has a higher concentration of negative charge and can easily donate its electrons.

**Hint:** Remember that nucleophiles act as Lewis bases, donating electron pairs to electrophiles.

### Step 2: Analyze the Given Species
Let's consider the species mentioned in the video:
1. OH⁻ (hydroxide ion)
2. CH₃OH (methanol)
3. CH₃O⁻ (methoxide ion)
4. CH₃S⁻ (thiolate ion)

**Hint:** Focus on the presence of negative charges and the electronegativity of the atoms involved.

### Step 3: Compare OH⁻ and CH₃O⁻
- **OH⁻** has a negative charge on oxygen.
- **CH₃O⁻** has a negative charge on oxygen but is also stabilized by the electron-donating effect of the methyl group (CH₃). This increases the electron density on the oxygen, making it a stronger nucleophile than OH⁻.

**Hint:** The presence of electron-donating groups (like CH₃) enhances nucleophilicity.

### Step 4: Compare CH₃O⁻ and CH₃S⁻
- **CH₃O⁻** (methoxide) has a negative charge on oxygen, which is more electronegative and holds onto its electrons more tightly.
- **CH₃S⁻** (thiolate) has a negative charge on sulfur, which is less electronegative than oxygen. This means sulfur can donate its electrons more readily compared to oxygen.

**Hint:** Remember that as you move down a group in the periodic table, electronegativity decreases, making the element more willing to donate electrons.

### Step 5: Conclusion
Comparing the nucleophilicity:
- **CH₃O⁻** is stronger than **OH⁻**.
- **CH₃S⁻** is stronger than **CH₃O⁻** due to lower electronegativity.

Thus, the strongest nucleophile among the options is **CH₃S⁻**.

**Final Answer:** The strongest nucleophile is **CH₃S⁻**.