Which has the highest melting point?

Options

A. `BeCl_2 `
B. `MgCl_2 `
C. `CaCl_2 `
D. `SrCl_2 `

Answer

To determine which compound has the highest melting point among the given options, we can follow these steps:

### Step 1: Understand Melting Point
The melting point of a substance is the temperature at which it changes from solid to liquid. It is influenced by various factors, including the charge of ions and the ionic radii.

### Step 2: Analyze the Factors Affecting Melting Point
1. **Charge of Ions**: Higher charges on cations or anions typically lead to stronger ionic bonds, resulting in a higher melting point.
2. **Ionic Radii**: A smaller ionic radius results in stronger ionic bonds due to the closer proximity of the ions, which also contributes to a higher melting point.

### Step 3: Compare the Given Compounds
Assuming we are comparing compounds like Beryllium Chloride (BeCl2), Magnesium Chloride (MgCl2), Calcium Chloride (CaCl2), and Strontium Chloride (SrCl2):
- The charge of the anions (Cl-) is the same for all compounds.
- The cationic radius increases down the group in the periodic table (Be < Mg < Ca < Sr).

### Step 4: Determine the Melting Points
- Beryllium Chloride (BeCl2): Highest melting point due to the smallest cation radius and highest charge density.
- Magnesium Chloride (MgCl2): Lower melting point than BeCl2 but higher than CaCl2 and SrCl2.
- Calcium Chloride (CaCl2): Lower melting point than MgCl2.
- Strontium Chloride (SrCl2): Lowest melting point among the four due to the largest cation radius.

### Step 5: Conclusion
Based on the analysis, Strontium Chloride (SrCl2) has the highest melting point among the given options.

### Final Answer
**Strontium Chloride (SrCl2) has the highest melting point.**

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