Which of the following is a test for proteins?

Options

A. Molisch's test
B. Beilstein test
C. Biuret test
D. Benedict's test

Answer

To determine which of the following is a test for proteins, we will analyze the options provided: Mollusk test, Ballistin test, Bayreuth test, and Benedict test.

### Step-by-Step Solution:

1. **Identify the Tests**: We have four tests to consider:
- Mollusk test
- Ballistin test
- Bayreuth test
- Benedict test

2. **Understand Protein Structure**: Proteins are made up of amino acids linked by peptide bonds. The peptide bond is characterized by a carbonyl group (C=O) and an amine group (NH).

3. **Identify the Correct Test**:
- The **Bayreuth test** is specifically designed to detect the presence of peptide bonds in proteins. It is a chemical test that confirms the presence of proteins by reacting with the peptide bonds.
- The **Benedict test** is used for reducing sugars, not proteins.
- The **Mollusk test** and **Ballistin test** are not standard tests for proteins.

4. **Components of the Bayreuth Test**: The reagent used in the Bayreuth test includes:
- Sodium hydroxide (NaOH) or potassium hydroxide (KOH)
- Hydrated copper sulfate (CuSO₄·5H₂O)
- Sodium potassium tartrate

5. **Conclusion**: Since the Bayreuth test is specifically used to detect proteins due to the presence of peptide bonds, it is the correct answer.

### Final Answer:
The correct test for proteins is the **Bayreuth test**.

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