Question

Assertion $K_4[Fe(CN{)}_6]$ is diamagnetic and $[Fe(H_{2}O{)}_6]C{l}_3$ is paramagnetic.
Reason Hybridisation of central metal m $K_4[Fe(CN{)}_6]iss{p}^3{d}^2,$ while in $[Fe(H_{2}O{)}_6]C{l}_{3}is{d}^{2}s{p}^3$

• 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)

In $K_4[Fe(CN{)}_6],Fe$ is present as $F{e}^{2+}$.
$F{e}^{2+}=[Ar]3d^6,4s^0$
Since, all eiecrons are paired, it is diamagnetic in nature. In $[Fe(H_{2}O{)}_6]C{l}_3$, Fe is present as $F{e}^{3+}$
$F{e}^{3+}=[Ar]3d^5,4s^0$
$[Fe(H_{2}O{)}_6{)}^{3+}=[Ar]$
Since, it contains five unpaired electrons, it is paramagnetic in nature.