Select the correct statement :

Options

A. `PH_(3)` is reduces `AgNO_(3)` to metallic Ag.
B. Organic tissues turn `AgNO_(3)` black by reducing it to Ag.
C. `AgCN` is soluble in KCN.
D. All are correct statements.

Answer

To solve the question, we need to evaluate each statement provided and determine which one is correct. Let's break it down step by step:

### Step 1: Analyze the first statement
The first statement claims that phosphine (pH3) reduces silver nitrate (AgNO3) to metallic silver (Ag).

**Analysis:**
- Phosphine (pH3) is known to act as a reducing agent.
- The reduction reaction can be represented as follows:
\[ 6 \text{AgNO}_3 + 3 \text{H}_3\text{P} \rightarrow 6 \text{Ag} + 3 \text{H}_2\text{O} + 6 \text{HNO}_3 \]
- This confirms that phosphine does indeed reduce silver nitrate to metallic silver.

**Conclusion:**
This statement is **true**.

### Step 2: Analyze the second statement
The second statement asserts that organic tissues turn AgNO3 black by reducing it to argentite (Ag).

**Analysis:**
- Organic tissues can reduce silver nitrate (AgNO3) to metallic silver (Ag).
- The finely divided metallic silver can appear black, which is often observed in photographic processes.
- The term "argentite" typically refers to a mineral form of silver sulfide (Ag2S) and is not the correct term here. However, the essence of the statement regarding the reduction to metallic silver is correct.

**Conclusion:**
This statement is **true** in the context of reduction to metallic silver, even though the term "argentite" is misleading.

### Step 3: Analyze the third statement
The third statement claims that silver cyanide (AgCN) is soluble in potassium cyanide (KCN).

**Analysis:**
- When AgCN is treated with KCN, it forms a soluble complex known as potassium argentocyanide:
\[ \text{AgCN} + 2 \text{KCN} \rightarrow \text{K}_2[\text{Ag(CN)}_2] \]
- This confirms that AgCN is indeed soluble in KCN.

**Conclusion:**
This statement is **true**.

### Final Conclusion
Since all three statements are true, the correct answer is that all statements are correct.