Which solid will have the weakest intermolecular forces?

Options

A. Ice
B. Phosphorus
C. Naphthalene
D. Sodium fluoride

Answer

To determine which solid has the weakest intermolecular forces, we can analyze the melting points of various solids. The melting point of a solid is an indicator of the strength of the intermolecular forces present in that solid. Here’s a step-by-step solution:

### Step 1: Understand Intermolecular Forces
Intermolecular forces are the forces of attraction or repulsion between neighboring molecules. The strength of these forces affects the physical properties of the substance, including its melting point.

**Hint:** Remember that stronger intermolecular forces lead to higher melting points.

### Step 2: Compare Melting Points
We can compare the melting points of different solids to infer the strength of their intermolecular forces. Generally, a lower melting point indicates weaker intermolecular forces.

**Hint:** Look for solids with known melting points to make comparisons.

### Step 3: Analyze Given Examples
From the video, we have the following melting points:
- Ice (H₂O): 0°C
- Paraffin (C₁₈H₃₈): 44°C
- Naphthalene (C₁₀H₈): 80°C
- Sodium Fluoride (NaF): 993°C

**Hint:** Identify which of these solids has the lowest melting point.

### Step 4: Identify the Solid with the Weakest Intermolecular Forces
Among the solids listed, ice has the lowest melting point (0°C). This indicates that ice has the weakest intermolecular forces compared to the other solids mentioned.

**Hint:** Recall that the solid with the lowest melting point will have the weakest intermolecular forces.

### Step 5: Conclusion
Based on the analysis, we conclude that ice (H₂O) has the weakest intermolecular forces among the solids compared.

**Final Answer:** Ice has the weakest intermolecular forces.