Which test can be used to distinguish propan-2-one and Propanal ?

Explanation

To distinguish between propan-2-one (a ketone) and propanal (an aldehyde), we can use the Tollens' reagent test. Here’s a step-by-step solution:

### Step 1: Identify the Compounds
- **Propan-2-one** (ketone) has the structure: CH3C(=O)CH3
- **Propanal** (aldehyde) has the structure: CH3CH2CHO

### Step 2: Understand the Test
- The Tollens' reagent is an ammoniacal silver nitrate solution, which is used to test for aldehydes. It is represented as Ag(NH3)2^+.

### Step 3: Perform the Test
- When propanal (the aldehyde) is treated with Tollens' reagent, it reduces the silver ions (Ag^+) to metallic silver, resulting in a silver mirror on the inner surface of the test tube.
- The reaction can be summarized as follows:
\[ RCHO + 2Ag(NH3)2^+ + 3OH^- \rightarrow RCOO^- + 2Ag + 2NH3 + 2H2O \]

### Step 4: Observe the Results
- **For Propanal**: A silver mirror forms, indicating a positive result.
- **For Propan-2-one**: No reaction occurs, and thus no silver mirror forms, indicating a negative result.

### Step 5: Conclusion
- The presence of a silver mirror confirms the presence of an aldehyde (propanal), while the absence of a reaction confirms the presence of a ketone (propan-2-one).

### Final Answer
The Tollens' reagent test can be used to distinguish between propan-2-one and propanal.

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