Question

$K_4[Fe(CN)_6]$ is diamagnetic and $[Fe(H_2O)_6 ]Cl_3$ is paramagnetic. Hybridisation of central metal m $K_4[Fe(CN)_6] is \,sp^3d^2,$ while in $[Fe(H_2O)_6]Cl_3\, is\, d^2\, sp^3$

• A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
• B. Both Assertion and Reason are true and Reason is not the correct explanation of Assertion.
• C. Assertion is true but Reason is false.
• D. Both Assertion and Reason are false.

Answer 1

Answer: (C)

Assertion is true but Reason is false.

Answer 2

In $K_4[Fe(CN)_6],Fe$ is present as $Fe^{2+}$. $Fe^{2+} = [Ar] 3d^6, 4s^0$ Since, all eiecrons are paired, it is diamagnetic in nature. In $[Fe(H_2O)_6]Cl_3$, Fe is present as $Fe^{3+}$ $Fe^{3+} = [Ar] 3d^5, 4s^0$ $[Fe(H_2O)_6)^{3+} =[Ar]$ Since, it contains five unpaired electrons, it is paramagnetic in nature.