An element combines with oxygen to give a compound with a high melting point. The compound is also soluble in water. The element is likely to be

Options

A. calcium
B. carbon
C. silicon
D. iron

Explanation

To determine the element that combines with oxygen to form a compound with a high melting point and is soluble in water, we can analyze the given options: calcium, carbon, silicon, and iron.

### Step-by-Step Solution:

1. **Identify the Compounds Formed by Each Element with Oxygen:**
- **Calcium (Ca)**: When calcium reacts with oxygen, it forms calcium oxide (CaO).
- **Carbon (C)**: When carbon reacts with oxygen, it forms carbon dioxide (CO₂).
- **Silicon (Si)**: When silicon reacts with oxygen, it forms silicon dioxide (SiO₂).
- **Iron (Fe)**: When iron reacts with oxygen, it forms iron oxide (Fe₂O₃).

2. **Analyze the Properties of the Compounds:**
- **Calcium Oxide (CaO)**: This compound is ionic and has a high melting point. It is also soluble in water, forming calcium hydroxide (Ca(OH)₂).
- **Carbon Dioxide (CO₂)**: This compound is a covalent molecule with a low melting point and is not soluble in water.
- **Silicon Dioxide (SiO₂)**: This compound has a high melting point but is not soluble in water.
- **Iron Oxide (Fe₂O₃)**: This compound has a high melting point but is not very soluble in water.

3. **Determine Which Element Meets All Criteria:**
- The criteria are:
- The compound must have a high melting point.
- The compound must be soluble in water.
- Among the compounds formed, only calcium oxide (CaO) meets both criteria.

4. **Conclusion:**
- Therefore, the element that combines with oxygen to give a compound with a high melting point and is soluble in water is **Calcium (Ca)**.

### Final Answer:
The element is likely to be **Calcium (Ca)**.

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