Match the complex ions given in Column I with the colours given the Column II and assign the correct code :
`{:(,"Column I (Complex ion)",,"Column II (Colour)"),("A".,[Co(NH_(3))_(6)]^(3+),1.,"Violet"),("B".,[Ti(H_(2)O)_(6)]^(3+),2.,"Green"),("C".,[Ni(H_(2)O)_(6)]^(2+),3.,"Pale blue"),("D".,[Ni(H_(2)O)_(4)(en)]^(2+)(aq),4.,"Yellowish organge"),(,,5.,"Blue"):}`

Options

A. `{:("A (1)","B (2)","C (4)","D (5)"):}`
B. `{:("A (4)","B (3)","C (2)","D (1)"):}`
C. `{:("A (3)","B (2)","C (4)","D (1)"):}`
D. `{:("A (4)","B (1)","C (2)","D (3)"):}`

Answer

To solve the problem of matching complex ions with their respective colors, we will follow these steps:

### Step 1: Identify the complex ions and their corresponding colors.
We have the following complex ions in Column I:
- A: [Co(NH₃)₆]³⁺
- B: [Ti(H₂O)₆]³⁺
- C: [Ni(H₂O)₆]²⁺
- D: [Ni(H₂O)₄(en)]²⁺

And the colors in Column II:
1. Violet
2. Green
3. Pale blue
4. Yellowish orange
5. Blue

### Step 2: Determine the color of each complex ion.
1. **[Co(NH₃)₆]³⁺**: This complex is known to exhibit a **yellowish orange** color.
2. **[Ti(H₂O)₆]³⁺**: This complex typically shows a **pale blue** color.
3. **[Ni(H₂O)₆]²⁺**: This complex is recognized for its **green** color.
4. **[Ni(H₂O)₄(en)]²⁺**: This complex is known to appear **violet**.

### Step 3: Match the complex ions with their colors.
Now we will match the complex ions from Column I with the colors in Column II based on our findings:
- A: [Co(NH₃)₆]³⁺ → 4. Yellowish orange
- B: [Ti(H₂O)₆]³⁺ → 3. Pale blue
- C: [Ni(H₂O)₆]²⁺ → 2. Green
- D: [Ni(H₂O)₄(en)]²⁺ → 1. Violet

### Step 4: Assign the correct codes.
Based on the matches:
- A → 4
- B → 3
- C → 2
- D → 1

### Final Answer:
The correct code for the matches is: **4, 3, 2, 1**.