In assigning R-S configuration which among the following groups has highest priority?

Options

A. `-SO_(3)H`
B. `-COOH`
C. `-CHO`
D. `-C_(6)H_(5)`

Answer

To determine which group has the highest priority in assigning R-S configuration, we will follow these steps:

### Step 1: Identify the Groups Attached to the Chiral Carbon
First, we need to identify the groups (A, B, C, D) that are attached to the chiral carbon. Each group will be compared based on the atomic number of the atoms directly attached to the chiral center.

### Step 2: Determine the Atomic Numbers of the Atoms in Each Group
Next, we will look at the atomic numbers of the atoms in each group:
- For example, if one group is SO₃H (sulfonic acid), the sulfur atom has an atomic number of 16.
- If another group is a carbon atom (C), it has an atomic number of 6.

### Step 3: Compare the Atomic Numbers
Now, we will compare the atomic numbers of the atoms in each group:
- Sulfur (16) vs. Carbon (6)
- If there are multiple carbons, they will still have the same atomic number (6).

### Step 4: Assign Priority Based on Atomic Numbers
The group with the highest atomic number will have the highest priority. In our example:
- SO₃H (sulfur, atomic number 16) has a higher priority than any group containing carbon (atomic number 6).

### Conclusion
Based on the atomic numbers, the group with the highest priority is SO₃H. Therefore, the correct answer is option A.