An organic reaction occurs by using reagents called electrophiles and nucleophiles via the formation of some reactive intermediates called carbocations, carbanions, free radicals, carbenes, nitrenes, radical cations, and radical anions.
Which of the following contains electrophiles only ?

Options

A. `Br^(oplus), PH_3, H_2O`
B. `NO_2^(oplus), : CBr_2, SO_3`
C. `NH_3,H_2 O, A1 Br_3`
D. `A1C1_3, CH_2=CH_2,SO_3`

Answer

To determine which of the given options contains only electrophiles, we need to analyze each option based on the definition of electrophiles. Electrophiles are species that are electron-deficient and can accept electrons. They often carry a positive charge or have an incomplete octet.

### Step-by-Step Solution:

1. **Identify the Electrophiles:**
- **Option 1: Br⁺ (Bromine cation)**
- Bromine with a positive charge is electron-deficient. Thus, Br⁺ is an electrophile.

- **Option 2: NO⁺ (Nitronium ion)**
- The nitronium ion (NO⁺) has a positive charge, indicating that it is electron-deficient. Therefore, NO⁺ is also an electrophile.

- **Option 3: CBr₂ (Dibromomethane)**
- In CBr₂, the carbon atom is bonded to two bromine atoms. The carbon is electron-deficient due to the higher electronegativity of bromine, making CBr₂ an electrophile.

- **Option 4: SO₃ (Sulfur trioxide)**
- In SO₃, the sulfur atom is surrounded by three highly electronegative oxygen atoms, making it electron-deficient. Thus, SO₃ is an electrophile.

- **Option 5: NH₃ (Ammonia)**
- Ammonia (NH₃) has a lone pair of electrons on nitrogen, making it electron-rich and not an electrophile.

- **Option 6: CH₂=CH₂ (Ethylene)**
- Ethylene has a double bond, which means it has high electron density. Therefore, it is electron-rich and not an electrophile.

2. **Conclusion:**
- From the analysis, options 1 (Br⁺), 2 (NO⁺), 3 (CBr₂), and 4 (SO₃) are all electrophiles. However, options 5 (NH₃) and 6 (CH₂=CH₂) do not contain only electrophiles.
- Therefore, the correct answer is **Option 2** (NO⁺, CBr₂, SO₃) as it contains only electrophiles.

### Final Answer:
**Option 2: NO⁺, CBr₂, SO₃ contains only electrophiles.**