The decreasing order of priority for the following functional group is:
I. `-COOH` II. `-SO_(3) H`
III. `-COOR` IV. `-COC1`

Options

A. `(IV)gt(III)gt(II)gt(I)`
B. `(I)gt(II)gt(III)gt(IV)`
C. `(II)gt(I)gt(III)gt(IV)`
D. `(IV)gt(III)gt(I)gt(II)`

Answer

To determine the decreasing order of priority for the given functional groups, we will analyze each functional group based on the established rules of nomenclature in organic chemistry.

### Step-by-Step Solution:

1. **Identify the Functional Groups**:
- I. `-COOH` (Carboxylic acid)
- II. `-SO₃H` (Sulphonic acid)
- III. `-COOR` (Ester)
- IV. `-COCl` (Acid chloride)

2. **Understand the Priority of Functional Groups**:
- In organic chemistry, functional groups have a specific order of priority when naming compounds. The priority affects how the compound is named and how it is classified.

3. **Rank the Functional Groups**:
- The priority order for the functional groups is as follows:
1. **Carboxylic acid (`-COOH`)**: This is the highest priority functional group among the ones listed.
2. **Sulphonic acid (`-SO₃H`)**: This comes next in priority after carboxylic acids.
3. **Ester (`-COOR`)**: Esters have a lower priority than both carboxylic and sulphonic acids.
4. **Acid chloride (`-COCl`)**: This has the lowest priority among the listed groups.

4. **Write the Decreasing Order**:
- Based on the analysis, the decreasing order of priority for the functional groups is:
- I. `-COOH` > II. `-SO₃H` > III. `-COOR` > IV. `-COCl`

### Final Answer:
The decreasing order of priority for the functional groups is:
**I. `-COOH` > II. `-SO₃H` > III. `-COOR` > IV. `-COCl`**