Which of the following statement is wrong?

Options

A. Alkyl halides follow the following reactivity sequece on reaction with alkanes
`R-I gt R-Br gt R-CI gt R-F`
B. the reaction of methyl magneisum bromide with acetone gives butanol-2
C. `C_(2)H_(4)CI_(2)` may exist in two isomeric forms
D. Ethyl chloride on reduction with `Zn-Cu` couple and alcohol gives ethane

Answer

To determine which statement is wrong, we will analyze each statement one by one.

### Step 1: Analyze the First Statement
**Statement:** Alkyl halides follow the following reactivity sequence on reaction with alkenes: RI > RBr > RCl > RF.

**Analysis:**
- The reactivity of alkyl halides in nucleophilic substitution reactions is influenced by the leaving group ability. The order of leaving group ability is based on the size of the halogen atom.
- Iodine (I) is the largest and thus the best leaving group, followed by bromine (Br), chlorine (Cl), and fluorine (F).
- Therefore, the sequence RI > RBr > RCl > RF is correct.

**Conclusion:** This statement is correct.

### Step 2: Analyze the Second Statement
**Statement:** The reaction of methyl magnesium bromide with acetone gives butanol or 2-butanol.

**Analysis:**
- Methyl magnesium bromide (CH3MgBr) is a Grignard reagent. When it reacts with acetone (CH3C(=O)CH3), it forms a tertiary alcohol.
- The product formed is 2-methylpropan-2-ol, also known as tert-butanol, not butanol or 2-butanol.

**Conclusion:** This statement is wrong.

### Step 3: Analyze the Third Statement
**Statement:** C2H4Cl2 may exist in two isomeric forms.

**Analysis:**
- C2H4Cl2 can exist as 1,1-dichloroethane (where both Cl are on the same carbon) and 1,2-dichloroethane (where Cl are on adjacent carbons).
- Therefore, this statement is correct as it can indeed exist in two isomeric forms.

**Conclusion:** This statement is correct.

### Step 4: Analyze the Fourth Statement
**Statement:** Ethyl chloride on reduction with ZnCu gives ethane.

**Analysis:**
- Ethyl chloride (C2H5Cl) when reduced with zinc-copper couple (ZnCu) in the presence of ethanol will yield ethane (C2H6) and zinc chloride (ZnCl2).
- This reaction is a well-known reduction reaction.

**Conclusion:** This statement is correct.

### Final Conclusion
After analyzing all the statements, the wrong statement is the second one: "The reaction of methyl magnesium bromide with acetone gives butanol or 2-butanol."

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