Which one of the following does not get oxidised by bromine water

Options

A. `Fe^(+2)` to `Fe^(+3)`
B. `Cu^(+)` to `Cu^(+2)`
C. `Mn^(+2)` to `MnO_(4)^(-)`
D. `Sn^(+2)` to `Sn^(+4)`

Answer

To determine which substance does not get oxidized by bromine water (Br2), we can use the concept of the electrochemical series (ECS). The electrochemical series ranks elements based on their standard electrode potentials, indicating their tendency to be oxidized or reduced.

### Step-by-Step Solution:

1. **Understanding Bromine Water**:
- Bromine water is a solution of bromine (Br2) in water, which is typically yellow in color. It acts as an oxidizing agent.

2. **Reviewing the Electrochemical Series**:
- In the electrochemical series, substances that are more negative (lower in the series) can reduce substances that are higher (more positive). Conversely, substances that are higher in the series cannot reduce those that are lower.

3. **Analyzing the Given Options**:
- We need to analyze the oxidation states and positions of the given options in the electrochemical series to determine which one does not get oxidized by bromine water.

4. **Identifying Each Substance**:
- **Fe²⁺ to Fe³⁺**: Iron (Fe) can be oxidized, and Fe²⁺ is lower than Br2 in the series, so it can oxidize bromine water.
- **Cu**: Copper (Cu) is lower in the series and does not get oxidized by bromine water.
- **Mn²⁺**: Manganese (Mn) in the +2 oxidation state is above bromine water in the series, so it can oxidize bromine water.
- **Sn²⁺**: Tin (Sn) in the +2 oxidation state is also below bromine water, so it can oxidize bromine water.

5. **Conclusion**:
- The substance that does not get oxidized by bromine water is **Copper (Cu)**, as it is lower in the electrochemical series compared to bromine.

### Final Answer:
Copper (Cu) does not get oxidized by bromine water.