Which one of the following compounds will give white precipitate
with tollen's reagent ?

Options

A. `CH_(3)underset(CH_(3))underset(|)(CH)-CH_(3)`
B. `CH_(3)-CH=CH_(2)`
C. `CH_(3)-C-=CH`
D. `CH_(3)-C-=C-CH_(3)`

Answer

To determine which compound will give a white precipitate with Tollens' reagent, we need to follow these steps:

### Step 1: Understand the Composition of Tollens' Reagent
Tollens' reagent is an ammoniacal silver nitrate solution, represented as Ag(NH₃)₂⁺. It is commonly used to test for the presence of aldehydes and terminal alkynes.

**Hint:** Remember that Tollens' reagent is specifically used for detecting certain types of organic compounds.

### Step 2: Identify the Types of Compounds
In the question, we are provided with different types of compounds: alkanes, alkenes, and alkynes. We need to identify which of these can react with Tollens' reagent.

**Hint:** Recall that not all hydrocarbons react with Tollens' reagent. Focus on the functional groups that are known to react.

### Step 3: Determine Reactivity with Tollens' Reagent
Among alkanes, alkenes, and alkynes, only terminal alkynes can react with Tollens' reagent to produce a white precipitate. This is due to the presence of a hydrogen atom attached to the carbon of the triple bond in terminal alkynes.

**Hint:** Terminal alkynes have a specific structure that allows them to react with Tollens' reagent. Look for the presence of a terminal hydrogen.

### Step 4: Write the Reaction
When a terminal alkyne reacts with Tollens' reagent, it forms a silver alkynide and water, resulting in a white precipitate of silver.

**Hint:** The reaction produces a solid precipitate. Consider what the products of the reaction indicate.

### Step 5: Conclusion
Based on the above analysis, the compound that will give a white precipitate with Tollens' reagent is a terminal alkyne. Therefore, the correct answer is the option that represents a terminal alkyne.

**Hint:** Review the options given in the question to identify which one corresponds to a terminal alkyne.

### Final Answer
The correct answer is the terminal alkyne (option number 3).