The decreasing nucleophillic order fo the following compounds is:
i. `F^(o-)`, ii. `Cl^(o-)`, iii. `Br^(o-)`, Iv. `I^(o-)`

Options

A. `(i) gt (ii) gt (iii) gt (iv)`
B. `(iv) gt (iii) gt (ii) gt (i)`
C. `(ii) gt (i) gt (iii) gt (iv)`
D. `(ii) gt (i) gt (iv) gt (iii)`

Explanation

To determine the decreasing nucleophilic order of the given halide ions (F⁻, Cl⁻, Br⁻, I⁻), we need to analyze their nucleophilic strength based on their electronegativity and size. Here’s a step-by-step solution:

### Step 1: Understand Nucleophilicity
Nucleophilicity refers to the ability of a species to donate an electron pair to an electrophile. Nucleophiles are electron-rich species that can be negatively charged or neutral.

### Step 2: Consider Electronegativity
The nucleophilic strength of an ion is inversely proportional to the electronegativity of the central atom. This means that as electronegativity increases, nucleophilicity decreases.

### Step 3: Analyze the Halide Ions
The halide ions in question are:
- Fluoride (F⁻)
- Chloride (Cl⁻)
- Bromide (Br⁻)
- Iodide (I⁻)

The electronegativity values of these halogens (from highest to lowest) are:
1. Fluorine (F) - highest electronegativity
2. Chlorine (Cl)
3. Bromine (Br)
4. Iodine (I) - lowest electronegativity

### Step 4: Determine Nucleophilic Strength
Since nucleophilicity increases as electronegativity decreases, we can arrange the halide ions in order of decreasing nucleophilicity:
- I⁻ (least electronegative, strongest nucleophile)
- Br⁻
- Cl⁻
- F⁻ (most electronegative, weakest nucleophile)

### Step 5: Write the Final Order
Thus, the decreasing nucleophilic order is:
**I⁻ > Br⁻ > Cl⁻ > F⁻**

### Conclusion
The correct answer for the decreasing nucleophilic order is:
**I⁻ > Br⁻ > Cl⁻ > F⁻**

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