Which one of the following has high melting and boiling points ?

Options

A. `C Cl_(4)`
B. `AlCl_(3)`
C. `CaCl_(2)`
D. `NCl_(3)`

Answer

To determine which compound has the highest melting and boiling points among the given options, we will analyze the nature of the compounds based on their cations and anions.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- We need to look at the compounds provided in the question. For this example, let's assume we have Calcium Chloride (CaCl₂), Aluminum Chloride (AlCl₃), Carbon Chloride (CCl₄), and Nitrogen Chloride (NCl₃).

2. **Analyze the Cations**:
- The cations in the compounds are Calcium (Ca²⁺), Aluminum (Al³⁺), Carbon (C⁴⁺), and Nitrogen (N³⁺).
- The size of the cation affects the melting and boiling points. Generally, larger cations lead to higher ionic character and thus higher melting and boiling points.

3. **Analyze the Anions**:
- All the compounds have Chloride (Cl⁻) as the anion. Since the anion is the same, we focus on the cation's size and charge.

4. **Compare the Cation Sizes**:
- Calcium (Ca) is located in Group 2 of the periodic table and is larger than Aluminum (Al), Carbon (C), and Nitrogen (N).
- Calcium has a larger ionic radius compared to Aluminum, Carbon, and Nitrogen.

5. **Determine Ionic Character**:
- The ionic character increases with the size of the cation. Calcium, being the largest cation among the given options, will have the highest ionic character.

6. **Conclusion**:
- Since Calcium has the largest size and the highest ionic character, Calcium Chloride (CaCl₂) will have the highest melting and boiling points among the given compounds.

### Final Answer:
**Calcium Chloride (CaCl₂) has the highest melting and boiling points.**