Which of the following is a false statement -

Options

A. Diethyl ether gives ethyl iodide on reacting with HI
B. Diethyl ether and methyl isopropyl ether are chain isomers
C. Diethyl ether is a Lewis base
D. Diethyl ether hydrolyses to ethanol by dil . `H_2SO_4`

Answer

To determine which of the statements regarding diethyl ether is false, we will analyze each option step by step.

### Step 1: Analyze the First Statement
The first statement claims that diethyl ether reacts with HI to produce ethyl iodide and ethanol.

- **Reaction**: Diethyl ether (CH3CH2OCH2CH3) reacts with HI.
- **Mechanism**: The ether oxygen attacks the proton (H+) from HI, forming an oxonium ion (CH3CH2O+CH2CH3). The iodide ion (I-) then attacks one of the ethyl groups, leading to the formation of ethyl iodide (CH3CH2I) and ethanol (CH3CH2OH).

**Conclusion**: This statement is true.

### Step 2: Analyze the Second Statement
The second statement claims that diethyl ether and methyl isopropyl ether are chain isomers.

- **Definition**: Chain isomers are compounds that have the same molecular formula but differ in the arrangement of the carbon skeleton.
- **Molecular Formula**: Diethyl ether (C4H10O) and methyl isopropyl ether (C5H12O) have different molecular formulas.

**Conclusion**: This statement is false because they are not chain isomers; they are different compounds with different molecular formulas.

### Step 3: Analyze the Third Statement
The third statement claims that diethyl ether is a Lewis base.

- **Definition**: A Lewis base is a substance that can donate an electron pair.
- **Mechanism**: Diethyl ether has lone pairs on the oxygen atom, allowing it to act as a Lewis base by donating electrons.

**Conclusion**: This statement is true.

### Step 4: Analyze the Fourth Statement
The fourth statement claims that diethyl ether hydrolyzes to ethanol by dilute H2SO4.

- **Reaction**: When diethyl ether is treated with dilute H2SO4, it can undergo hydrolysis.
- **Mechanism**: The ether oxygen abstracts a proton from H2SO4, forming an oxonium ion, which then reacts with water to yield ethanol.

**Conclusion**: This statement is true.

### Final Conclusion
After analyzing all statements, we find that the second statement is false. Therefore, the answer to the question is:

**The false statement is: "Diethyl ether and methyl isopropyl ether are chain isomers."**

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