Which of the following compound is expected to be colourless

Options

A. `ScO`
B. `V_(2)O_(3)`
C. `CuCN`
D. `Cr_(2)(SO_(4))_(3)`

Explanation

To determine which compound is expected to be colorless, we need to analyze the electronic configurations and oxidation states of the given compounds. A compound is typically colorless if it has no unpaired electrons in its electronic configuration.

### Step-by-Step Solution:

1. **Identify the Compounds**: The question provides several compounds. We need to analyze each one to find out which is colorless.

2. **Analyze Scandium Oxide (Sc2O3)**:
- **Oxidation State**: Scandium typically exhibits a +3 oxidation state in its oxide.
- **Electronic Configuration**: The electronic configuration of Scandium (Sc) is [Ar] 3d¹ 4s². In the +3 state, it loses 3 electrons (2 from 4s and 1 from 3d), resulting in 3d⁰.
- **Conclusion**: Since there are no unpaired electrons (3d⁰), Scandium oxide is colorless.

3. **Analyze Vanadium Oxide (V2O3)**:
- **Oxidation State**: Vanadium typically exhibits a +3 oxidation state in V2O3.
- **Electronic Configuration**: The electronic configuration of Vanadium (V) is [Ar] 4s² 3d³. In the +3 state, it loses 3 electrons (2 from 4s and 1 from 3d), resulting in 3d².
- **Conclusion**: Since there are unpaired electrons (3d²), V2O3 is colored.

4. **Analyze Copper(I) Cyanide (CuCN)**:
- **Oxidation State**: Copper in CuCN has a +1 oxidation state.
- **Electronic Configuration**: The electronic configuration of Copper (Cu) is [Ar] 4s² 3d¹⁰. In the +1 state, it loses one electron from the 4s orbital, resulting in 3d¹⁰.
- **Conclusion**: Since there are no unpaired electrons (3d¹⁰), CuCN is colorless.

5. **Analyze Chromium(III) Sulfate (Cr2(SO4)3)**:
- **Oxidation State**: Chromium typically exhibits a +3 oxidation state in this compound.
- **Electronic Configuration**: The electronic configuration of Chromium (Cr) is [Ar] 4s² 3d⁵. In the +3 state, it loses 3 electrons (2 from 4s and 1 from 3d), resulting in 3d⁴.
- **Conclusion**: Since there are unpaired electrons (3d⁴), Cr2(SO4)3 is colored.

6. **Final Conclusion**: Among the analyzed compounds, **CuCN** is the only compound that is expected to be colorless due to the absence of unpaired electrons.

### Answer:
The compound expected to be colorless is **CuCN**.