Arrange priority of CIP sequence of given groups in decreasing order -
(I) `OH`
(II) `COOH`
(III) `CHOHCH_(3)`
(IV) `CH_(2)OH`

Options

A. I gt II gt III gt IV
B. IV gt III gt II gt I
C. II gt III gt IV gt I
D. IV gt I gt II gt III

Answer

To arrange the priority of the given groups according to the Cahn-Ingold-Prelog (CIP) priority rules, we will follow these steps:

### Step 1: Identify the Atoms in Each Group
- **Group I (OH)**: Contains oxygen (O) and hydrogen (H).
- **Group II (COOH)**: Contains carbon (C), oxygen (O), and hydrogen (H).
- **Group III (CHOHCH₃)**: Contains carbon (C) and hydrogen (H) in a hydroxyl (OH) group.
- **Group IV (CH₂OH)**: Contains carbon (C), hydrogen (H), and a hydroxyl (OH) group.

### Step 2: Determine Atomic Mass
According to the CIP rules, we assign priority based on the atomic mass of the atoms directly attached to the chiral center:
- Oxygen (O) has a higher atomic mass than carbon (C).
- Therefore, any group containing oxygen will have a higher priority than those containing only carbon.

### Step 3: Assign Priority Based on Atomic Mass
1. **Group II (COOH)**: Contains oxygen, which has the highest atomic mass among the groups.
2. **Group I (OH)**: Contains oxygen, but only has one oxygen atom compared to COOH which has two.
3. **Group III (CHOHCH₃)**: Contains carbon and has a hydroxyl group, but the carbon is attached to two hydrogens and one hydroxyl group.
4. **Group IV (CH₂OH)**: Contains carbon and has a hydroxyl group, but the carbon is attached to two hydrogens.

### Step 4: Compare Remaining Groups
Now we compare Group III (CHOHCH₃) and Group IV (CH₂OH):
- Group III (CHOHCH₃) has a carbon that is attached to two different groups (hydroxyl and a methyl group).
- Group IV (CH₂OH) has a carbon that is attached to two hydrogens and a hydroxyl group.

Since Group III has more diversity in its substituents, it will have a higher priority than Group IV.

### Final Priority Order
Based on the analysis:
1. **Group II (COOH)** - Highest priority
2. **Group I (OH)**
3. **Group III (CHOHCH₃)**
4. **Group IV (CH₂OH)** - Lowest priority

Thus, the final order in decreasing priority is:
**COOH > OH > CHOHCH₃ > CH₂OH**