Which of the following molecule involves electrovalent bond?

Options

A. `H_(2)`
B. `CH_(4)`
C. `CaCl_(2)`
D. `HCl`

Explanation

To determine which molecule involves an electrovalent bond (also known as an ionic bond), we need to understand the characteristics of electrovalent bonds and analyze the given molecules.

### Step-by-Step Solution:

1. **Define Electrovalent Bond**:
An electrovalent bond is formed between ions of opposite charges. It occurs when one atom donates an electron to another atom, resulting in the formation of positively charged cations and negatively charged anions. The electrostatic attraction between these oppositely charged ions constitutes the electrovalent bond.

**Hint**: Remember that electrovalent bonds are formed between ions, not between atoms that share electrons.

2. **Identify the Molecules**:
Let's consider the molecules mentioned in the question. The question does not specify which molecules to analyze, but common examples include H2, CH4, and CaCl2.

3. **Analyze Each Molecule**:
- **H2 (Hydrogen)**: This molecule consists of two hydrogen atoms sharing electrons. Therefore, it is held together by a covalent bond, not an electrovalent bond.
- **CH4 (Methane)**: This molecule consists of one carbon atom and four hydrogen atoms. The bonds formed here involve the sharing of electrons between carbon and hydrogen, making it a covalent compound.
- **CaCl2 (Calcium Chloride)**: This molecule consists of calcium ions (Ca²⁺) and chloride ions (Cl⁻). The bond between these ions is due to the electrostatic attraction between the positively charged calcium ion and the negatively charged chloride ions, which is characteristic of an electrovalent bond.

4. **Conclusion**:
Among the molecules analyzed, **CaCl2** is the one that involves an electrovalent bond.

### Final Answer:
The molecule that involves an electrovalent bond is **CaCl2 (Calcium Chloride)**.