Alkali metal salt "X" gives a pale violet colour in flame test "X" is :

Options

A. NaCl
B. LiCl
C. KCl
D. None of these

Answer

To determine which alkali metal salt "X" gives a pale violet color in a flame test, we can follow these steps:

### Step 1: Understand the Flame Test
The flame test is a qualitative analysis technique used to identify the presence of certain metal ions based on the color they emit when heated in a flame. Different metal ions produce characteristic colors.

**Hint:** Remember that the color observed in the flame test is due to the excitation of electrons in the metal ions.

### Step 2: Identify the Given Options
The options provided are:
- NaCl (Sodium Chloride)
- AlCl (Aluminum Chloride)
- KCl (Potassium Chloride)
- None of these

**Hint:** Focus on the cation in each salt, as it is responsible for the color produced in the flame test.

### Step 3: Analyze Each Option
1. **NaCl (Sodium Chloride)**: The cation is Na⁺. When heated, Na⁺ produces a bright yellow color in the flame.
2. **AlCl (Aluminum Chloride)**: The cation is Al³⁺. Aluminum does not produce a characteristic flame color and is not typically used in flame tests.
3. **KCl (Potassium Chloride)**: The cation is K⁺. When heated, K⁺ produces a pale violet color in the flame.
4. **None of these**: This option suggests that none of the provided salts produce a pale violet color, which we need to verify.

**Hint:** Pay attention to the characteristic colors associated with each alkali metal ion.

### Step 4: Conclusion
Based on the analysis:
- Na⁺ gives yellow
- Al³⁺ does not give a distinct flame color
- K⁺ gives pale violet

Thus, the alkali metal salt "X" that gives a pale violet color in the flame test is **KCl (Potassium Chloride)**.

**Final Answer:** X is KCl.