Few drop of `HNO_(3)` are added to II group if before preceeding to group III in order to :

Options

A. Covert `Fe^(2+)` to `Fe^(3+)`
B. Convert` Fe^(3+)` to `Fe^(2+)`
C. ppt group III
D. None of these

Explanation

To answer the question regarding why a few drops of HNO₃ are added to the II group before proceeding to group III, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Groups**: In qualitative analysis, the II group typically contains cations such as Fe²⁺ (ferrous ions) and other metal ions that can form precipitates. The III group contains cations that are usually precipitated out of solution under specific conditions.

2. **Role of HNO₃**: HNO₃ (Nitric Acid) is known to act as an oxidizing agent. When added to a solution containing Fe²⁺ ions, it can oxidize these ions to Fe³⁺ ions.

3. **Oxidation Reaction**: The reaction can be represented as follows:
\[ 3Fe^{2+} + 6HNO_3 \rightarrow 3Fe^{3+} + 3NO + 3H_2O \]
In this reaction, Fe²⁺ is oxidized to Fe³⁺, and nitric oxide (NO) is released.

4. **Importance of Oxidation**: The conversion of Fe²⁺ to Fe³⁺ is crucial because Fe²⁺ ions can form soluble ferrous hydroxide (Fe(OH)₂), which does not precipitate effectively in the presence of water. In contrast, Fe³⁺ can form ferric hydroxide (Fe(OH)₃), which is less soluble and precipitates out of solution.

5. **Conclusion**: Therefore, the addition of HNO₃ is necessary to ensure that all ferrous ions are converted to ferric ions, allowing for proper precipitation of the hydroxides in the subsequent steps of the analysis.

### Final Answer:
The correct reason for adding a few drops of HNO₃ to the II group before proceeding to group III is **to convert Fe²⁺ to Fe³⁺**.