When a metal rod M is dipped into an aqueous colourless concetrated solution of compound N, the solution turns light blue. Addition of aqueous NaCl to the blue solution gives a white precipitate O. Addition of aqueous `NH_3` dissolves O and gives an intense blue solution.
Q. The final solution contains.

Options

A. `[Ph(NH_3)_4]^(2+)` and `[ClCl_4]^(2-)`
B. `[Al(NH_3)_4]^(3+)` and `[Cu(NH_3)_4]^(2+)`
C. `[Ag(NH_3)_2]^(o+)` and `[Cu(NH_3)_4]^(4+)`
D. `[Ag(NH_3)_2]^(o+)` and `[Ni(NH_3)_6]^(2+)`

Explanation

To solve the question step by step, let's analyze the information provided and deduce the final solution's composition.

### Step 1: Identify the metal rod M and compound N
- The metal rod M is likely copper (Cu) because when it is dipped into a concentrated colorless solution, the solution turns light blue. This indicates the formation of a copper ion (Cu²⁺) in solution, which is characteristic of copper(II) compounds.

### Step 2: Understand the formation of the light blue solution
- When the metal rod M (copper) is dipped into the colorless concentrated solution of compound N, it likely reacts to form a copper(II) ion solution, which is blue in color. The compound N is likely a copper salt, such as copper(II) nitrate (Cu(NO₃)₂).

### Step 3: Addition of NaCl and formation of white precipitate O
- When aqueous NaCl is added to the blue solution, a white precipitate O is formed. This suggests that a reaction occurs where silver ions (Ag⁺) are present, leading to the formation of silver chloride (AgCl), which is a white precipitate. This indicates that the solution likely contains silver ions.

### Step 4: Addition of aqueous NH₃
- The addition of aqueous ammonia (NH₃) dissolves the white precipitate O (AgCl) and results in an intense blue solution. This is characteristic of the formation of a silver ammonia complex, specifically [Ag(NH₃)₂]⁺. The intense blue color is associated with the copper ammonia complex, [Cu(NH₃)₄]²⁺.

### Step 5: Conclusion about the final solution
- The final solution contains both copper and silver complexes. Specifically, it contains:
- The copper ammonia complex: [Cu(NH₃)₄]²⁺ (intense blue)
- The silver ammonia complex: [Ag(NH₃)₂]⁺ (which is colorless but present in the solution)

### Final Answer
The final solution contains copper and silver complexes.