Question

Which of the following compounds will be repelled when placed in an external magnetic field?

• A. \( \text{FeCl}_3 \)
• B. \( \text{FeSO}_4 \)
• C. \( \text{NaCl} \)
• D. \( \text{CuSO}_4 \)

Hint:

Substances with unpaired electrons are paramagnetic and are attracted to a magnetic field, while substances without unpaired electrons are diamagnetic and are repelled. A quick way to determine this is by checking the electron configuration of the atoms or ions involved.

Answer 1

The Correct Option is C

In the context of magnetic behavior, compounds are classified based on their response to an external magnetic field. These substances can be classified as diamagnetic, paramagnetic, or ferromagnetic:
1. Diamagnetic substances: These materials are weakly repelled by a magnetic field and do not have unpaired electrons. The electrons in diamagnetic substances are all paired, so there is no net magnetic moment. Therefore, diamagnetic compounds are repelled by an external magnetic field. An example of this is \( \text{NaCl} \), which is a diamagnetic substance.
2. Paramagnetic substances: These materials are weakly attracted to a magnetic field because they contain unpaired electrons that align with the field. However, their magnetic effect is weaker compared to ferromagnetic substances. \( \text{FeCl}_3 \) is an example of a paramagnetic substance, as it contains unpaired electrons in the iron ion (\( Fe^{3+} \)).
3. Ferromagnetic substances: These substances have a strong attraction to magnetic fields due to the alignment of unpaired electrons in a coordinated manner. This phenomenon occurs in materials like iron, cobalt, and nickel.
Now, analyzing the options:
- \( \text{FeCl}_3 \) is paramagnetic and will be attracted to an external magnetic field because of the unpaired electrons in iron
. - \( \text{FeSO}_4 \) is also paramagnetic due to the unpaired electrons in \( Fe^{2+} \), and will be attracted to the magnetic field.
- \( \text{NaCl} \) is diamagnetic, which means it is repelled by the external magnetic field due to all paired electrons in the sodium and chloride ions.
- \( \text{CuSO}_4 \) is paramagnetic because copper in the \( \text{Cu}^{2+} \) state has unpaired electrons, so it will also be attracted to the magnetic field.
Thus, the correct answer is \( \text{NaCl} \), as it will be repelled due to its diamagnetic nature.