Which of the following compounds does not have an ester linkage ?

Options

A. Ethyl acid sulphate
B. Diethyl hydrogen phosphate
C. Ethyl acetate
D. `CH_(3) CO-O-CO-CH_(3)`

Answer

To determine which of the given compounds does not have an ester linkage, we need to analyze each option based on the definition of an ester linkage. An ester linkage is characterized by the presence of a carbonyl group (C=O) adjacent to an ether group (–O–), typically represented as RCOOR'.

Let's analyze each option step by step:

### Step 1: Analyze Ethyl Acid Sulfate
- **Structure**: Ethyl acid sulfate can be represented as CH3CH2OSO3H.
- **Linkage**: The structure contains a sulfur atom bonded to oxygen and does not have the typical ester linkage (RCOOR').
- **Conclusion**: Ethyl acid sulfate does not have an ester linkage.

### Step 2: Analyze Diethyl Hydrogen Phosphate
- **Structure**: Diethyl hydrogen phosphate can be represented as (C2H5)2OPO(OH)2.
- **Linkage**: This compound contains phosphorus and oxygen but does not exhibit the ester linkage (RCOOR').
- **Conclusion**: Diethyl hydrogen phosphate does not have an ester linkage.

### Step 3: Analyze Ethyl Acetate
- **Structure**: Ethyl acetate can be represented as CH3COOCH2CH3.
- **Linkage**: This compound has a carbonyl group (C=O) adjacent to an ether group (–O–), which confirms the presence of an ester linkage.
- **Conclusion**: Ethyl acetate has an ester linkage.

### Step 4: Analyze the Last Compound
- **Structure**: The last compound can be represented as CH3C(=O)OCH3.
- **Linkage**: This compound also has a carbonyl group (C=O) adjacent to an ether group (–O–), indicating the presence of an ester linkage.
- **Conclusion**: This compound has an ester linkage.

### Final Conclusion:
From the analysis, both Ethyl Acid Sulfate and Diethyl Hydrogen Phosphate do not have an ester linkage. However, if we focus on the options provided, the one that is most commonly recognized as lacking an ester linkage is **Diethyl Hydrogen Phosphate**.

### Answer:
**Diethyl Hydrogen Phosphate does not have an ester linkage.**

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