Silver, mercury and lead are grouped together in the same group of qualitative analysis because they form:

Options

A. nitrates
B. carbonates which dissolve in dill. `HNO_(3)`
C. insoluble chlorides
D. colourless compounds

Explanation

To solve the question of why silver, mercury, and lead are grouped together in qualitative analysis, we can follow these steps:

### Step 1: Identify the Elements
We are considering three elements: silver (Ag), mercury (Hg), and lead (Pb).

### Step 2: Understand the Concept of Qualitative Analysis
Qualitative analysis is a method used to determine the presence of certain ions or compounds in a sample. In this case, we are focusing on the behavior of these metals when they react with chlorine.

### Step 3: Reaction with Chlorine
When these metals react with chlorine (Cl2), they form chlorides. We need to look at the specific reactions:

1. **Silver Reaction**:
- Reaction: \( 2Ag + Cl_2 \rightarrow 2AgCl \)
- Result: Silver chloride (AgCl) is formed, which is insoluble in water.

2. **Mercury Reaction**:
- Reaction: \( Hg + Cl_2 \rightarrow Hg_2Cl_2 \)
- Result: Mercurous chloride (Hg2Cl2) is formed, which is also insoluble in water.

3. **Lead Reaction**:
- Reaction: \( Pb + Cl_2 \rightarrow PbCl_2 \)
- Result: Lead(II) chloride (PbCl2) is formed, which is insoluble in water.

### Step 4: Conclusion on Solubility
All three chlorides (AgCl, Hg2Cl2, and PbCl2) are insoluble in water, which is a key characteristic that groups these metals together in qualitative analysis.

### Final Answer
Silver, mercury, and lead are grouped together in qualitative analysis because they form insoluble chlorides when they react with chlorine.

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