A substance `X` is a compound of an element of group `1 A` the substance `X` gives a violet colour in flame test, `X` is

Options

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

Answer

To solve the problem, we need to identify the substance \( X \) based on the given clues. The clues indicate that \( X \) is a compound of an element from group 1A of the periodic table and that it produces a violet color during a flame test.

### Step-by-Step Solution:

1. **Identify Group 1A Elements**:
- The elements in group 1A (alkali metals) include Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), and Cesium (Cs).

2. **Analyze the Flame Test Colors**:
- Each alkali metal produces a characteristic color when subjected to a flame test:
- **Lithium (Li)**: Produces a dark red color.
- **Sodium (Na)**: Produces an orange-yellow color.
- **Potassium (K)**: Produces a violet color.
- **Rubidium (Rb)**: Produces a red-violet color.
- **Cesium (Cs)**: Produces a blue color.

3. **Match the Flame Test Color with the Element**:
- The problem states that substance \( X \) gives a violet color in the flame test. From the list above, we can see that Potassium (K) is the only element that produces a violet color.

4. **Determine the Compound**:
- Since we are looking for a compound of an element from group 1A that gives a violet color, the most common compound of Potassium that fits this description is Potassium Chloride (KCl).

5. **Conclusion**:
- Therefore, the substance \( X \) is **Potassium Chloride (KCl)**.

### Final Answer:
Substance \( X \) is Potassium Chloride (KCl).