Propyne and propene can be distinguished by `:`

Options

A. Conc. `H_(2)SO_(4)`
B. `Br_(2)` in `C Cl_(4)`
C. Dil. `KMnO_(4)`
D. `AgNO_(3)` in ammonia

Explanation

To distinguish between propyne (an alkyne) and propene (an alkene), we can use the Tollen's test, which involves the use of silver nitrate (AgNO3) in ammonia. Here's a step-by-step solution:

### Step-by-Step Solution:

1. **Identify the Compounds**:
- Propyne (C3H4) is an alkyne with a triple bond.
- Propene (C3H6) is an alkene with a double bond.

2. **Choose the Test**:
- We will use the Tollen's test, which involves AgNO3 in ammonia. This test is specific for terminal alkynes.

3. **Reaction with Propyne**:
- When propyne reacts with AgNO3 in ammonia, the terminal hydrogen of the alkyne is replaced by a silver ion (Ag+), forming a silver acetylide and producing a white precipitate of silver.
- The reaction can be represented as:
\[ \text{H}_3\text{C}-\text{C} \equiv \text{C} + \text{AgNO}_3 + \text{NH}_3 \rightarrow \text{H}_3\text{C}-\text{C} \equiv \text{C} \text{Ag} + \text{HNO}_3 \]
- This results in the formation of a white precipitate of silver acetylide.

4. **Reaction with Propene**:
- When propene is treated with AgNO3 in ammonia, there is no reaction since propene does not have a terminal hydrogen that can be replaced by silver.
- The reaction can be represented as:
\[ \text{H}_3\text{C}-\text{C}=\text{CH}_2 + \text{AgNO}_3 + \text{NH}_3 \rightarrow \text{No Reaction} \]

5. **Conclusion**:
- The formation of a white precipitate with propyne and no reaction with propene allows us to distinguish between the two compounds. Therefore, we can conclude that the correct method to distinguish propyne from propene is by using AgNO3 in ammonia.

### Final Answer:
Propyne and propene can be distinguished by **AgNO3 in ammonia**.