Which of the following does/do not impart characteristic colour to the flame?

Options

A. `MgSO_(4)`
B. `CaCl_(2)`
C. `Sr(NO_(3))_(2)`
D. `BeCl_(2)`

Answer

To solve the question of which of the following compounds does not impart a characteristic color to the flame, we will analyze the behavior of different alkaline earth metals when subjected to flame tests.

### Step-by-Step Solution:

1. **Understanding Flame Colors**:
- When certain metal salts are heated in a flame, their valence electrons absorb energy and get excited to higher energy levels. When these electrons return to their ground state, they release energy in the form of light, which corresponds to specific colors.

2. **Identifying the Metals**:
- The question involves alkaline earth metals, specifically beryllium (Be), magnesium (Mg), calcium (Ca), and strontium (Sr).

3. **Analyzing Each Metal**:
- **Beryllium (Be)**: Beryllium does not impart any characteristic flame color due to its small atomic size and high ionization energy. The energy from the flame is insufficient to excite its valence electrons.
- **Magnesium (Mg)**: Similar to beryllium, magnesium also does not impart any characteristic color to the flame for the same reasons: high ionization energy and small atomic size.
- **Calcium (Ca)**: Calcium salts, such as CaCl2, produce a characteristic brick-red color in the flame.
- **Strontium (Sr)**: Strontium compounds, like Sr(NO3)2, yield a bright red color in the flame.

4. **Conclusion**:
- The compounds that do not impart characteristic color to the flame are magnesium (Mg) and beryllium (Be). Therefore, the answer to the question is that both magnesium and beryllium do not impart any characteristic color to the flame.

### Final Answer:
- Magnesium (Mg) and Beryllium (Be) do not impart characteristic color to the flame.