Which of the following is a correct statement?

Options

A. Aq.solutions of `Cu^(+)` and `Zn^(2+)` are colourless
B. Aq. solutions of `Cu^(2+) and Zn^(2+)` are colour less
C. Aqueous solutions of `Fe^(3+)` is green in colour
D. Aqueous solutions of `MnO_(4)^(-)` is colourless Magnetic properties

Answer

To determine the correct statement regarding the color of the aqueous solutions of various ions, we will analyze each option based on the electronic configurations and the presence of unpaired electrons.

### Step-by-Step Solution:

1. **Understanding the Ions:**
- We need to evaluate the color of the aqueous solutions of Cu⁺, Cu²⁺, Zn²⁺, Fe³⁺, and MnO₄⁻.

2. **Analyzing Cu⁺:**
- **Atomic Number of Copper (Cu)**: 29
- **Electronic Configuration of Cu**: [Ar] 3d¹⁰ 4s¹
- **For Cu⁺**: The electronic configuration becomes [Ar] 3d¹⁰.
- **Color**: Cu⁺ has no unpaired electrons (3d¹⁰), thus its aqueous solution is colorless.

3. **Analyzing Cu²⁺:**
- **For Cu²⁺**: The electronic configuration becomes [Ar] 3d⁹.
- **Color**: Cu²⁺ has one unpaired electron (3d⁹), leading to color in its aqueous solution.

4. **Analyzing Zn²⁺:**
- **Atomic Number of Zinc (Zn)**: 30
- **Electronic Configuration of Zn**: [Ar] 3d¹⁰ 4s²
- **For Zn²⁺**: The electronic configuration becomes [Ar] 3d¹⁰.
- **Color**: Zn²⁺ has no unpaired electrons (3d¹⁰), thus its aqueous solution is colorless.

5. **Analyzing Fe³⁺:**
- **Atomic Number of Iron (Fe)**: 26
- **For Fe³⁺**: The electronic configuration becomes [Ar] 3d⁵.
- **Color**: Fe³⁺ has five unpaired electrons (3d⁵), leading to a yellow color in its aqueous solution.

6. **Analyzing MnO₄⁻:**
- **For MnO₄⁻**: Manganate ion has Mn in the +7 oxidation state.
- **Electronic Configuration of Mn (Atomic Number 25)**: [Ar] 3d⁵ 4s²
- **For MnO₄⁻**: The electronic configuration is effectively [Ar] 3d⁰ (after losing 7 electrons).
- **Color**: MnO₄⁻ is colored due to the presence of unpaired electrons in its higher oxidation state.

7. **Conclusion:**
- The correct statements based on the analysis are:
- Aqueous solutions of Cu⁺ and Zn²⁺ are colorless.
- Aqueous solution of Cu²⁺ is colored.
- Aqueous solution of Fe³⁺ is yellow, not green.
- Aqueous solution of MnO₄⁻ is colored.

### Final Answer:
The correct statement is: "Aqueous solution of Cu⁺ and Zn²⁺ are colorless."