Two soluble salts of iron A & B,on combining | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) is $FeCl_{2}$ and $B$ is $FeCl_{3}$. The reagent $(R)$ is $KCN$. $C$ is $K_{4}[Fe(CN)_{6}]$ (pale yellow) and $D$ is $K_{3}[Fe(CN)_{6}]$ (yellow).

Vedclass · Accepted Answer

Blue colour of the compound is due to $d-d$ transition

Vedclass · Answer

(A) is $FeCl_{2}$ and $B$ is $FeCl_{3}$. The reagent $(R)$ is $KCN$. $C$ is $K_{4}[Fe(CN)_{6}]$ (pale yellow) and $D$ is $K_{3}[Fe(CN)_{6}]$ (yellow). Reaction of $A$ $(Fe^{2+})$ with $D$ $([Fe(CN)_{6}]^{3-})$ gives $Fe_{3}[Fe(CN)_{6}]_{2}$ (Turnbull's blue). Reaction of $B$ $(Fe^{3+})$ with $C$ $([Fe(CN)_{6}]^{4-})$ gives $Fe_{4}[Fe(CN)_{6}]_{3}$ (Prussian blue). Both are blue coloured compounds. The blue colour in these complexes is due to metal-to-metal charge transfer $(MMCT)$ between $Fe^{2+}$ and $Fe^{3+}$,not $d-d$ transition. $C$ $([Fe(CN)_{6}]^{4-})$ is diamagnetic ($d^{6}$,low spin),while $D$ $([Fe(CN)_{6}]^{3-})$ is paramagnetic ($d^{5}$,low spin). Thus,the statement that the blue colour is due to $d-d$ transition is incorrect,and the statement about paramagnetism is only true for $D$.

Two soluble salts of iron $A$ & $B$,on combining with excess of a reagent $(R)$ produce compound $C$ (pale yellow) & $D$ (yellow) respectively. Reaction of $A$ with $D$ and that of $B$ with $C$ both produce a blue coloured compound. Which of the following statements is correct?

Similar Questions

Which of the following complex ions is expected to absorb light in the visible region?

In which of the following orders are the given complex ions arranged correctly with respect to their decreasing spin-only magnetic moment?
$(i)$ $[FeF_{6}]^{3-}$
$(ii)$ $[Co(NH_{3})_{6}]^{3+}$
$(iii)$ $[NiCl_{4}]^{2-}$
$(iv)$ $[Cu(NH_{3})_{4}]^{2+}$

In the coordination complex $[CoF_6]^{3-}$,the number of unpaired electrons is equal to ......

$A$ compound absorbs light in the wavelength region $490-500 \,nm$. Its complementary colour is

Explain why $[Fe(H_{2}O)_{6}]^{3+}$ has a magnetic moment value of $5.92 \ BM$ whereas $[Fe(CN)_{6}]^{3-}$ has a value of only $1.74 \ BM$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module