Chloride of which of the following elements will be coloured

Options

A. Silver
B. Mercury
C. Zinc
D. Coblat

Explanation

To determine which chloride among the given elements is colored, we need to analyze the electronic configurations of the elements and their chlorides. The presence of unpaired electrons in the d-orbitals of transition metals is what typically gives rise to color in their compounds.

### Step-by-Step Solution:

1. **Identify the Elements**: The elements provided are Silver (Ag), Mercury (Hg), Zinc (Zn), and Cobalt (Co).

2. **Determine Electronic Configurations**:
- **Silver (Ag)**: Atomic number = 47
- Electronic Configuration: [Kr] 4d¹⁰ 5s¹
- In the d-orbital, there are 10 electrons (fully filled).

- **Mercury (Hg)**: Atomic number = 80
- Electronic Configuration: [Xe] 4f¹⁴ 5d¹⁰ 6s²
- In the d-orbital, there are 10 electrons (fully filled).

- **Zinc (Zn)**: Atomic number = 30
- Electronic Configuration: [Ar] 3d¹⁰ 4s²
- In the d-orbital, there are 10 electrons (fully filled).

- **Cobalt (Co)**: Atomic number = 27
- Electronic Configuration: [Ar] 4s² 3d⁷
- In the d-orbital, there are 7 electrons (which means there are unpaired electrons).

3. **Analyze the Presence of Unpaired Electrons**:
- **Silver (Ag)**: No unpaired electrons (colorless).
- **Mercury (Hg)**: No unpaired electrons (colorless).
- **Zinc (Zn)**: No unpaired electrons (colorless).
- **Cobalt (Co)**: Has unpaired electrons (colored).

4. **Conclusion**: The chloride of Cobalt will be colored due to the presence of unpaired electrons in its d-orbitals.

### Final Answer:
The chloride of Cobalt (Co) will be colored.

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