Ammonical `AgNO_(3)` gives white ppt after reaction with any compound then this reflects the presence of

Options

A. One-CHO group
B. One triple bond
C. A terminal alkyne
D. Compound is unsaturated

Answer

To solve the question, we need to identify what the white precipitate formed by ammoniacal silver nitrate (Tollens' reagent) indicates. Here's a step-by-step breakdown of the solution:

### Step 1: Understand the Composition of Ammoniacal Silver Nitrate
Ammoniacal silver nitrate is a solution made by mixing silver nitrate (AgNO₃) with ammonium hydroxide (NH₄OH). This mixture is commonly known as Tollens' reagent.

**Hint:** Remember that Tollens' reagent is used to test for specific functional groups in organic compounds.

### Step 2: Identify the Reaction with Different Functional Groups
Tollens' reagent is known for its ability to react with certain organic compounds:
- It reacts with aldehydes (CHO group) to produce a carboxylic acid and a silver mirror, but not a white precipitate.
- It reacts with terminal alkynes (RC≡CH) to produce a white precipitate of silver acetylide (AgC≡C-R).

**Hint:** Focus on the types of compounds that react with Tollens' reagent and the products formed.

### Step 3: Determine the White Precipitate Formation
When terminal alkynes react with Tollens' reagent, the acetylenic hydrogen is abstracted, leading to the formation of a white precipitate of silver acetylide (AgC≡C-R). This is the key reaction that produces the white precipitate.

**Hint:** Recall that terminal alkynes contain a hydrogen atom bonded to a carbon that is part of a triple bond, which is essential for the reaction to occur.

### Step 4: Conclusion
Based on the reactions discussed, the presence of a white precipitate when ammoniacal silver nitrate is added indicates the presence of a terminal alkyne.

**Final Answer:** The white precipitate reflects the presence of a terminal alkyne (Option C).