The spin-only magnetic moments of $\left[\mathrm{Fe}\left(\mathrm{NH}_{3}\right)_{6}\right]^{3+}$ and $\left[\mathrm{FeF}_{6}\right]^{3-\text { in }} \mathrm{BM}$ are, respectively,

• A

  $1.73$ and $1.73$
• B

  $5.92$ and $1.73$
• Correct answer
  C

  $1.73$ and $5.92$
• D

  $5.92$ and $5.92$

Solution

$$ \begin{array}{l} \mathrm{Fe}^{3+}=3 \mathrm{~d}^{5} \\ \end{array} $$
$\odot$ ${F}$ is $W F L$ so $\mu=5.92$ While $\mathrm{NH}_{3}$ is SFL \& pairing of electrons takes place so $\mu=1.73$

Hence, the correct answer is option: 'C'.