Consider the following complex ions P, Q and R: `P=[FeF_6]^(3-), Q=[V(H_2O_6)]^(2+) ,R=[Fe(H_2O)_6]^(2+)` The correct order of the complex ionis, according to their spin-only magnetic moment values (in BM)is

Options

A. R `lt` Q `lt` P
B. Q `lt` R `lt` P
C. R `lt` P `lt` Q
D. Q `lt` P `lt` R .

Answer

B

Explanation

The outer electronic configurations of the central metal ions are as follows:

The number of unpaired electrons in P=5,Q=3 and R=4. From the relation `mu = sqrt(n(n+2))`, where n is the number of unpaired electrons, we have the order of spin only magnetic moment as `Q lt R lt P`.