When LiCl is doped with Li vapours the colour developed is

Options

A. Violet
B. Yellow
C. Pink
D. Green

Answer

To determine the color developed when LiCl is doped with Li vapors, we can follow these steps:

### Step 1: Understand the Process of Doping
When lithium chloride (LiCl) crystals are heated in an atmosphere of lithium vapor, lithium atoms are introduced into the crystal structure.

**Hint:** Doping involves introducing impurities into a crystal to modify its properties.

### Step 2: Ionization of Lithium
Lithium, being an alkali metal, tends to lose an electron easily. When heated, lithium atoms lose an electron to form lithium ions (Li⁺).

**Hint:** Alkali metals have a tendency to lose one electron to achieve a stable electron configuration.

### Step 3: Formation of F Centers
The released electrons from the lithium atoms do not just disappear; they diffuse into the crystal lattice of LiCl. These electrons occupy vacant ionic sites in the crystal lattice, which are referred to as F centers (or color centers).

**Hint:** F centers are created when an electron occupies a site that would normally be occupied by an anion in the crystal lattice.

### Step 4: Color Imparted by F Centers
The presence of these F centers, which contain the free electrons, imparts a specific color to the crystal. In the case of LiCl doped with Li vapors, the color developed is pink.

**Hint:** The color observed in doped crystals is often due to the presence of these color centers.

### Conclusion
Therefore, when LiCl is doped with Li vapors, the color developed is pink.

**Final Answer:** Pink

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