Which of the following weighs less when weighed in magnetic field?

Options

A. `ScCl_(3)`
B. `FeCl_(3)`
C. `TiCl_(3)`
D. `VCl_(3)`

Answer

To solve the question "Which of the following weighs less when weighed in a magnetic field?", we need to identify the magnetic properties of the given compounds. The key points to remember are:

1. **Diamagnetic substances**: These substances have all their electrons paired and are repelled by a magnetic field, resulting in a decrease in weight when weighed in such a field.
2. **Paramagnetic substances**: These have unpaired electrons and are attracted to a magnetic field, hence they do not weigh less.

Now, let's analyze the given compounds step by step:

### Step 1: Analyze SeCl3 (Selenium trichloride)
- **Oxidation state of Selenium (Se)**: In SeCl3, Se is in the +3 oxidation state.
- **Electronic configuration**: The electronic configuration of Se in this state is Argon (Ar), 3d^0, 4s^0.
- **Unpaired electrons**: There are no unpaired electrons in this configuration.
- **Conclusion**: Since SeCl3 is diamagnetic, it will weigh less in a magnetic field.

### Step 2: Analyze FeCl3 (Iron(III) chloride)
- **Oxidation state of Iron (Fe)**: In FeCl3, Fe is in the +3 oxidation state.
- **Electronic configuration**: The electronic configuration of Fe in this state is Argon (Ar), 3d^5, 4s^0.
- **Unpaired electrons**: There are five unpaired electrons in the 3d subshell.
- **Conclusion**: Since FeCl3 is paramagnetic, it will not weigh less in a magnetic field.

### Step 3: Analyze TiCl3 (Titanium(III) chloride)
- **Oxidation state of Titanium (Ti)**: In TiCl3, Ti is in the +3 oxidation state.
- **Electronic configuration**: The electronic configuration of Ti in this state is Argon (Ar), 3d^1, 4s^0.
- **Unpaired electrons**: There is one unpaired electron in the 3d subshell.
- **Conclusion**: Since TiCl3 is paramagnetic, it will not weigh less in a magnetic field.

### Step 4: Analyze VCl3 (Vanadium(III) chloride)
- **Oxidation state of Vanadium (V)**: In VCl3, V is in the +3 oxidation state.
- **Electronic configuration**: The electronic configuration of V in this state is Argon (Ar), 3d^2, 4s^0.
- **Unpaired electrons**: There are two unpaired electrons in the 3d subshell.
- **Conclusion**: Since VCl3 is paramagnetic, it will not weigh less in a magnetic field.

### Final Conclusion
After analyzing all the compounds, we find that:
- **SeCl3** is the only compound that is diamagnetic and will weigh less in a magnetic field.

### Answer: SeCl3 weighs less when weighed in a magnetic field.

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