The deecreasing leaving group order of the following compounds is:
i. `overset(o-)(C)H_(3)`, ii. `overset(o-)(N)H_(2)`, iii. `overset(o-)(O)H`, iv. `F^(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 leaving group order of the given compounds, we need to analyze the basic strength of the leaving groups, as leaving group strength is inversely proportional to basic strength.

### Step-by-Step Solution:

1. **Identify the Compounds**: The compounds given are:
- i. `overset(o-)(C)H_(3)` (methanide ion, CH3^-)
- ii. `overset(o-)(N)H_(2)` (amide ion, NH2^-)
- iii. `overset(o-)(O)H` (hydroxide ion, OH^-)
- iv. `F^(o-)` (fluoride ion, F^-)

2. **Understand Basic Strength**: Basic strength is a measure of how readily a species can accept a proton (H+). The stronger the base, the weaker the leaving group.

3. **Electronegativity Consideration**: The central atoms of the anions belong to the same period (period 2). The electronegativity order for the relevant elements is:
- F > O > N > C
This means that as we move from F to C, the basic strength increases.

4. **Determine Basic Strength**: Based on electronegativity, we can deduce the basic strength of the anions:
- CH3^- (least electronegative, strongest base)
- NH2^- (next, strong base)
- OH^- (moderate base)
- F^- (most electronegative, weakest base)

5. **Establish Leaving Group Order**: Since leaving group strength is inversely related to basic strength:
- F^- (weakest base, strongest leaving group)
- OH^- (moderate base, next strongest leaving group)
- NH2^- (stronger base, weaker leaving group)
- CH3^- (strongest base, weakest leaving group)

6. **Final Order**: The final order of leaving groups from strongest to weakest is:
- F^- > OH^- > NH2^- > CH3^-

### Conclusion:
The decreasing order of leaving group strength for the given compounds is:
**F^- > OH^- > NH2^- > CH3^-**