Which of the following is a displacement reaction?

Options

A. `CaO+H_(2)OtoCa(OH)_(2)`
B. `MgCO_(3)toMgO+CO_(2)`
C. `2Na+2H_(2)Oto2NaOH+H_(2)`
D. `H_(2)+Cl_(2)to2HCl`

Explanation

To determine which of the following is a displacement reaction, we first need to understand what a displacement reaction is. A displacement reaction occurs when a more reactive element displaces a less reactive element from its compound.

Now, let's analyze the options provided:

1. **Option A: Calcium Oxide + H2O → Ca(OH)2**
- This reaction involves two reactants combining to form one product, which is characteristic of a combination reaction. Therefore, this is **not** a displacement reaction.

2. **Option B: MgCO3 → MgO + CO2**
- This reaction is a decomposition reaction where a single compound breaks down into two products. Since it does not involve the displacement of one element by another, this is also **not** a displacement reaction.

3. **Option C: 2Na + 2H2O → 2NaOH + H2**
- In this reaction, sodium (Na) is more reactive than hydrogen (H). Sodium displaces hydrogen from water, forming sodium hydroxide (NaOH) and releasing hydrogen gas (H2). This is a clear example of a displacement reaction.

4. **Option D: H2 + Cl2 → 2HCl**
- This reaction involves the combination of hydrogen and chlorine to form hydrochloric acid (HCl). Since it does not involve one element displacing another from a compound, this is also **not** a displacement reaction.

Based on the analysis, the correct answer is **Option C: 2Na + 2H2O → 2NaOH + H2**, which is a displacement reaction.