CaO does not react with

Options

A. `SiO_2`
B. `P_4O_10`
C. `CO_2`
D. `MgO`

Answer

To determine which compound does not react with calcium oxide (CaO), we need to analyze the nature of each given compound and its potential reaction with CaO.

### Step-by-Step Solution:

1. **Identify the Nature of Calcium Oxide (CaO)**:
- Calcium oxide is a basic oxide. Basic oxides typically react with acidic oxides to form salts.

2. **Analyze Each Option**:
- **Option 1: SiO2 (Silicon Dioxide)**:
- SiO2 is an acidic oxide. Since CaO is basic, it can react with SiO2 to form calcium silicate (CaSiO3). Therefore, CaO reacts with SiO2.

- **Option 2: P4O10 (Phosphorus Pentoxide)**:
- P4O10 is also an acidic oxide. CaO can react with P4O10 to form calcium phosphate (Ca3(PO4)2). Thus, CaO reacts with P4O10.

- **Option 3: CO2 (Carbon Dioxide)**:
- CO2 is another acidic oxide. CaO can react with CO2 to form calcium carbonate (CaCO3). Hence, CaO reacts with CO2.

- **Option 4: MgO (Magnesium Oxide)**:
- MgO is a basic oxide, similar to CaO. Basic oxides do not typically react with each other. Therefore, CaO does not react with MgO.

3. **Conclusion**:
- The compound that does not react with calcium oxide is **Option 4: MgO**.

### Final Answer:
**CaO does not react with MgO.**

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