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

The complex ion $[Pt(NO_2)(py)(NH_3)(NH_2OH)]^{+}$ exhibits how many geometric isomers?

Which ion has the least value of theoretical magnetic moment?

Which of the following will be able to show geometrical isomerism?

The number of geometric isomers for the complex $[Co(NO_2)_2(NH_3)_2]$ is .....

The experimental value of the magnetic moment of a $Mn^{2+}$ complex salt is $5.96 \ BM$. This indicates that ......

Vedclass Test Series

Exam Paper Generator

Online Exam Module