Few simple chemical tests are given below to differentiate between the pairs of compounds.Which of the following tests is not correct for differentiation ?

Options

A. Propanal and propanone - Silver mirror test
B. Acetophenone and benzophenone - Iodoform test
C. Ethanal and propanal - Fehling's test
D. Benzoic acid and ethyl benzoate - Sodium bicarbonate test

Explanation

To solve the question of which chemical test is not correct for differentiating between the given pairs of compounds, we will analyze each pair and the respective tests provided.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- **Pair 1**: Propanol (an aldehyde) and Propanone (a ketone).
- **Pair 2**: Acetophenone (a ketone) and Benzophenone (a ketone).
- **Pair 3**: Ethanol (an aldehyde) and Propanol (an aldehyde).
- **Pair 4**: Benzoic acid (a carboxylic acid) and Ethyl benzoate (an ester).

2. **Analyze the Tests for Each Pair**:
- **For Pair 1 (Propanol vs. Propanone)**:
- **Test**: Silver mirror test (Tollens' test).
- **Result**: Propanol (aldehyde) will give a positive result (silver mirror formation), while Propanone (ketone) will not react. This test is valid for differentiation.

- **For Pair 2 (Acetophenone vs. Benzophenone)**:
- **Test**: Iodoform test.
- **Result**: Acetophenone contains an alpha-methyl group and will give a positive iodoform test, while Benzophenone does not have an alpha-methyl group and will not react. This test is valid for differentiation.

- **For Pair 3 (Ethanol vs. Propanol)**:
- **Test**: Fehling's test.
- **Result**: Both Ethanol and Propanol are aldehydes and will both react with Fehling's solution, giving a positive result. Thus, this test cannot differentiate between the two compounds. This test is **not valid** for differentiation.

- **For Pair 4 (Benzoic acid vs. Ethyl benzoate)**:
- **Test**: Sodium bicarbonate test.
- **Result**: Benzoic acid will react with sodium bicarbonate to produce carbon dioxide bubbles, while Ethyl benzoate will not react. This test is valid for differentiation.

3. **Conclusion**:
- The test that is not correct for differentiation is the test used for **Pair 3 (Ethanol and Propanol)**, as both compounds will react similarly and cannot be distinguished using Fehling's test.

### Final Answer:
The test that is not correct for differentiation is the **Fehling's test for Ethanol and Propanol**.

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