Which of the following is the strongest nucleophile ?

Options

A. `EtO^(Ө)`
B. `overset (Ө) O H`
C. `overset (Ө) C N`
D. `I^(Ө)`

Explanation

To determine which of the given species is the strongest nucleophile among ETO⁻, OH⁻, CN⁻, and I⁻, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Nucleophilicity**: Nucleophilicity refers to the ability of a species to donate an electron pair to an electrophile. Stronger nucleophiles are typically more reactive.

2. **Factors Affecting Nucleophilicity**: The strength of a nucleophile can be influenced by several factors:
- **Charge**: Anions are generally stronger nucleophiles than neutral species.
- **Electronegativity**: Less electronegative atoms are better nucleophiles because they hold onto their electrons less tightly.
- **Solvent Effects**: The solvent can stabilize or destabilize the nucleophile.
- **Steric Hindrance**: Bulky groups can hinder the approach of the nucleophile to the electrophile.

3. **Evaluate the Given Options**:
- **ET⁻ (Ethoxide)**: This is a strong nucleophile due to its negative charge and relatively low electronegativity of oxygen.
- **OH⁻ (Hydroxide)**: Also a strong nucleophile, but slightly less basic than ethoxide.
- **CN⁻ (Cyanide)**: A strong nucleophile due to the negative charge and the carbon atom's ability to donate electrons.
- **I⁻ (Iodide)**: While it is a negatively charged species, iodine is more electronegative and larger, making it a weaker nucleophile compared to the others.

4. **Compare Basicity**: Basicity can be a good indicator of nucleophilicity. The order of basicity for these species is:
- ETO⁻ > OH⁻ > CN⁻ > I⁻
This order suggests that ETO⁻ is the strongest base and therefore the strongest nucleophile.

5. **Conclusion**: Based on the evaluation of the options and their basicity, ETO⁻ (Ethoxide) is determined to be the strongest nucleophile among the given choices.

### Final Answer:
**ET⁻ (Ethoxide) is the strongest nucleophile.**