The increasing order of nucleophilicity is:

Options

A. `I^(-) lt Cl^(-) lt Br^-`
B. `Br^(-) lt Cl^(-) lt I^-`
C. `Cl^(-) lt Br^(-) lt I^-`
D. `I^(-) lt Br^(-) lt Cl^(-)`

Explanation

To determine the increasing order of nucleophilicity among the given halides (I^-, Br^-, Cl^-), we need to consider the size of the anions and their ability to donate electron pairs.

### Step-by-Step Solution:

1. **Understand Nucleophilicity**: Nucleophilicity refers to the ability of a species to donate an electron pair to an electrophile. Generally, larger anions are better nucleophiles because they can stabilize the negative charge more effectively.

2. **Identify the Anions**: The anions given in the question are I^-, Br^-, and Cl^-.

3. **Determine the Size of Anions**: The size of the halide ions increases as we move down the group in the periodic table:
- Cl^- (Chloride) is the smallest.
- Br^- (Bromide) is larger than Cl^-.
- I^- (Iodide) is the largest.

4. **Relate Size to Nucleophilicity**: Since nucleophilicity increases with the size of the anion, we can establish the following relationship:
- I^- > Br^- > Cl^-

5. **Write the Increasing Order of Nucleophilicity**: The increasing order of nucleophilicity among the given anions is:
- Cl^- < Br^- < I^-

### Final Answer:
The increasing order of nucleophilicity is: **Cl^- < Br^- < I^-**

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