Which of the following reactions would generated an electrolphile?
(I) `(CH_(3))_(3)CBr+"Anly. AlCl"_(3)`
(II) `CH_(3)-CH=CH_(2)+overset(o+)H`
(III) `C_(6)H_(5)COOH+H_(3)overset(o+)O`
(IV) `HNO_(3)+H_(2)SO_(4)`

Options

A. I, II and IV
B. I, II and III
C. I, II, III and IV
D. II, III and IV

Answer

To determine which of the given reactions generates an electrophile, we need to analyze each reaction step by step. An electrophile is an electron-deficient species that can accept an electron pair.

### Step-by-Step Solution

1. **Reaction I: (CH₃)₃CBr + Anhydrous AlCl₃**
- In this reaction, the bromine atom (Br) in tert-butyl bromide ((CH₃)₃CBr) has a lone pair of electrons. When it reacts with anhydrous AlCl₃, a Lewis acid, the AlCl₃ coordinates with the Br atom, leading to the formation of a carbocation (tert-butyl cation) and a bromide ion (Br⁻).
- **Formation of Electrophile:** The tert-butyl cation ((CH₃)₃C⁺) is an electrophile because it is electron-deficient.

2. **Reaction II: CH₃-CH=CH₂ + H⁺**
- Here, we have an alkene (propene). When it reacts with a proton (H⁺), the double bond can act as a nucleophile and attack the proton. This results in the formation of a carbocation (CH₃-CH⁺-CH₃).
- **Formation of Electrophile:** The carbocation formed is also an electrophile due to its electron deficiency.

3. **Reaction III: C₆H₅COOH + H₃O⁺**
- In this case, benzoic acid (C₆H₅COOH) is reacting with hydronium ion (H₃O⁺). The acid does not generate a new electrophile in this scenario, as the reaction leads to protonation of the carboxyl group, but no new electrophile is formed.
- **Conclusion:** No electrophile is generated in this reaction.

4. **Reaction IV: HNO₃ + H₂SO₄**
- In this reaction, concentrated sulfuric acid (H₂SO₄) acts as a dehydrating agent and protonates nitric acid (HNO₃). This leads to the formation of the nitronium ion (NO₂⁺) when water is eliminated.
- **Formation of Electrophile:** The nitronium ion (NO₂⁺) is a well-known electrophile.

### Summary of Electrophile Generation
- **Reactions that generate electrophiles:**
- Reaction I: (CH₃)₃CBr + AlCl₃ → Generates (CH₃)₃C⁺
- Reaction II: CH₃-CH=CH₂ + H⁺ → Generates CH₃-CH⁺-CH₃
- Reaction IV: HNO₃ + H₂SO₄ → Generates NO₂⁺

- **Reaction that does not generate an electrophile:**
- Reaction III: C₆H₅COOH + H₃O⁺ → No electrophile generated.

### Final Answer
The reactions that generate an electrophile are:
- I, II, and IV.