which of the following is an electrophilic reagent?

Options

A. `H_(2)O`
B. `NH_(3)`
C. `OH^(-)`
D. `Cl^+`

Explanation

To determine which of the given options is an electrophilic reagent, we need to understand what an electrophile is. An electrophile is a species that is electron-deficient and can accept electrons from a nucleophile (an electron-rich species).

Let's analyze each option step by step:

### Step 1: Analyze Option 1 - Water (H2O)
- **Structure**: Water has a bent structure with oxygen bonded to two hydrogen atoms.
- **Electron Count**: Oxygen has 6 valence electrons and forms two bonds with hydrogen, leaving it with two lone pairs (4 electrons).
- **Conclusion**: Water has an abundance of electrons due to its lone pairs and does not attract more electrons. Therefore, it is not an electrophile; it acts as a nucleophile.

### Step 2: Analyze Option 2 - Ammonia (NH3)
- **Structure**: Ammonia has a trigonal pyramidal shape with nitrogen bonded to three hydrogen atoms.
- **Electron Count**: Nitrogen has 7 valence electrons and forms three bonds with hydrogen, leaving it with one lone pair (2 electrons).
- **Conclusion**: Similar to water, ammonia has a lone pair of electrons and does not seek additional electrons. Thus, it is not an electrophile; it is also a nucleophile.

### Step 3: Analyze Option 3 - Hydroxide Ion (OH⁻)
- **Structure**: The hydroxide ion consists of an oxygen atom bonded to a hydrogen atom with an extra electron due to the negative charge.
- **Electron Count**: Oxygen has 6 valence electrons. The negative charge adds one more electron, giving it a total of 8 electrons (4 pairs).
- **Conclusion**: The hydroxide ion has an excess of electrons and does not attract more electrons. Therefore, it is not an electrophile; it is a nucleophile.

### Step 4: Analyze Option 4 - Chlorine Ion (Cl⁺)
- **Structure**: The chlorine ion has a positive charge.
- **Electron Count**: Chlorine normally has 7 valence electrons, but the positive charge indicates it is electron-deficient.
- **Conclusion**: The positive charge on chlorine means it is seeking electrons to stabilize itself. Therefore, it is an electrophile.

### Final Answer:
Based on the analysis, the correct answer is **Option 4: Chlorine Ion (Cl⁺)**, as it is the only electrophilic reagent among the options provided.

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