Which of the following respond to borax test ?

Options

A. Nickel salts
B. Copper salts
C. Cobalt salt
D. Aluminium salt

Answer

To determine which of the given metals respond to the borax bead test, we will analyze the properties of the metals in question. The borax bead test is a qualitative analysis method used primarily to detect the presence of certain transition metals based on their ability to impart color to a borax bead when heated in a flame.

### Step-by-Step Solution:

1. **Understand the Borax Bead Test**:
- The borax bead test is used to identify transition metals. When heated, certain metals can form colored compounds in the borax bead, indicating their presence.

2. **Identify the Metals in the Options**:
- The question provides a list of metals. We need to identify which of these metals are transition metals and which are not.

3. **Recognize Colorless Ions**:
- Metals that form colorless ions (such as Zinc, Aluminum, Calcium, and Barium) do not respond to the borax bead test. This is because they do not undergo d-d transitions that would impart color.

4. **Analyze Each Metal**:
- **Nickel (Ni)**: Nickel ions are colored and will respond to the borax bead test.
- **Copper (Cu)**: Copper salts are also colored and will respond to the borax bead test.
- **Cobalt (Co)**: Cobalt ions are colored and will respond to the borax bead test.
- **Aluminum (Al)**: Aluminum ions are colorless and will not respond to the borax bead test.

5. **Conclusion**:
- Based on the analysis, Nickel, Copper, and Cobalt respond to the borax bead test, while Aluminum does not.

### Final Answer:
Nickel, Copper, and Cobalt respond to the borax bead test.

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