Which of the following equation represents first enthalpy of ionization ?

Options

A. `Hg_((s)) rarr Hg_((g))^(+) +e^(-)`
B. `Hg_((l)) rarr Hg_((g))^(+) +e^(-)`
C. `Hg_((g)) rarr Hg_((g))^(+) +e^(-)`
D. `Hg_((g)) rarr Hg_((g))^(2+) +e^(-)`

Answer

To determine which equation represents the first enthalpy of ionization, we need to understand the definition and characteristics of this concept. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Definition
The first enthalpy of ionization is defined as the energy required to remove one mole of electrons from one mole of isolated gaseous atoms.

### Step 2: Identify the Process
The process can be represented by the following general equation:
\[ \text{A(g)} \rightarrow \text{A}^+(g) + e^- \]
Where:
- A(g) is the gaseous atom.
- A^+(g) is the gaseous cation formed after the removal of one electron.
- \( e^- \) is the electron that is removed.

### Step 3: Analyze the Options
Now, we need to look at the provided options (which are not listed here) and identify which one corresponds to the equation we derived in Step 2. The correct equation should show the transformation of a gaseous atom to a gaseous cation with the release of one electron.

### Step 4: Conclusion
Based on the definition and the process, the equation that matches the description of the first enthalpy of ionization will be the correct answer.

### Final Answer
The correct option that represents the first enthalpy of ionization is the one that shows:
\[ \text{A(g)} \rightarrow \text{A}^+(g) + e^- \]

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