Question

What will be the theoretical value of spin only magnetic moment when $Fe{(SCN)_3}$rests with the solution containing ${F^ - }$ions to yield a complex?
A.$2.83B.M.$
B.$3.87B.M.$
C.$5.92B.M.$
D.$1.73B.M.$

Answer 1

Hint: The magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field. Examples of objects that have magnetic moments include: loops of electric current, permanent magnets, elementary particles such as electrons, various molecules, and many astronomical objects.

Complete answer:
The term magnetic moment normally refers to a system's magnetic dipole moment, the component of the magnetic moment that can be represented by an equivalent magnetic dipole: a magnetic north and south pole separated by a very small distance. The magnetic dipole component is sufficient for small enough magnets or for large enough distances. Higher-order terms such as the magnetic quadrupole moment may be needed in addition to the dipole moment for extended objects.
The formula to find the spin magnetic moment is $\mu = \sqrt {n + (n + 2)} $, where n is the number of unpaired electrons.
Reaction between $Fe{(SCN)_3}$and ${F^ - }$$Fe{(SCN)_3} + 3{F^ - } \to Fe{F_3} + 3SC{N^ - }$
Magnetic moment = $\mu = \sqrt {n + (n + 2)} $
$ \Rightarrow \sqrt {5 \times 7} $
$ \Rightarrow \sqrt {35} $
$ \Rightarrow 5.92B.M.$
So, the correct answer is (C) $5.92B.M.$

Additional information:
The effective magnetic moment is a convenient measure of a material's magnetic properties because it is independent of temperature as well as external field strength for diamagnetic and paramagnetic materials.

Note:
The magnetic field of a magnetic dipole is proportional to its magnetic dipole moment. The dipole component of an object's magnetic field is symmetric about the direction of its magnetic dipole moment, and decreases as the inverse cube of the distance from the object.