Which compound releases bromide gas at anode ?

Options

A. Lead(II) bromide
B. Copper (II) oxide
C. Sodium chloride
D. Copper(II) Sulphate

Explanation

To determine which compound releases bromide gas at the anode during electrolysis, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Electrolysis**:
- Electrolysis is a process that uses electricity to break down a compound into its components. This occurs in an electrolytic cell, which has two electrodes: the anode (positive) and the cathode (negative).

2. **Identifying the Compounds**:
- The question asks which compound releases bromine gas at the anode. The options provided are:
- a) Lead bromide (PbBr2)
- b) Copper oxide (CuO)
- c) Sodium chloride (NaCl)
- d) Copper sulfate (CuSO4)

3. **Analyzing Lead Bromide (PbBr2)**:
- When lead bromide is electrolyzed, it dissociates into lead ions (Pb²⁺) and bromide ions (Br⁻).
- The reaction can be represented as:
\[ \text{PbBr}_2 \rightarrow \text{Pb}^{2+} + 2\text{Br}^- \]
- At the anode, oxidation occurs. The bromide ions (Br⁻) will lose electrons to form bromine gas (Br₂):
\[ 2\text{Br}^- \rightarrow \text{Br}_2 + 2e^- \]
- Therefore, bromine gas is released at the anode.

4. **Analyzing Other Compounds**:
- **Copper Oxide (CuO)**: This compound does not contain bromine, so it cannot release bromine gas.
- **Sodium Chloride (NaCl)**: This compound contains chloride ions (Cl⁻), not bromide ions, so it cannot release bromine gas.
- **Copper Sulfate (CuSO4)**: This compound also does not contain bromine, so it cannot release bromine gas.

5. **Conclusion**:
- The only compound that releases bromine gas at the anode during electrolysis is **Lead Bromide (PbBr2)**.

### Final Answer:
**Lead Bromide (PbBr2)** releases bromine gas at the anode.