Magnetic Moment Examples

Q.

Among the following allotropic forms of sulphur, the number of allotropic forms, which will show paramagnetism is ______.

1. $\mathrm{\alpha }-\mathrm{sulphur}$

2. $\mathrm{\beta }-\mathrm{sulphur}$

3. ${\mathrm{S}}_2-\mathrm{form}$

Q. $\left[NiC{l}_2\right\{P\left(C_2{H}_5{)}_2\right(C_6{H}_5\left){\}}_2\right]$ exhibits temperature dependent magnetic behaviour (paramagnetic/diamagnetic). The coordination geometry of $N{i}^{2+}$ in the paramagnetic and diamagnetic states are respectively:

1. Tetrahedral in both
2. Square planar in both
3. Tetrahedral and square planar
4. Square planar and tetrahedral

Q. How many of the following ions have spin magnetic moment more than four B.M.?
$T{i}^{3+},C{u}^{+},N{i}^{2+},F{e}^{3+},M{n}^{2+},C{o}^{2+}$

Q. The correct order of the spin only magnetic moment of metal ions in the following low spin complexes, $\left[V\right(CN{)}_6{]}^{4-}$ , $\left[Fe\right(CN{)}_6{]}^{4-}$, $\left[Ru\right(N{H}_3{)}_6{]}^{3+}$ and $\left[Cr\right(N{H}_3{)}_6{]}^{2+}$ is:

1. $C{r}^{2+}>R{u}^{3+}>F{e}^{2+}>V^{2+}$
2. $V^{2+}>C{r}^{2+}>R{u}^{3+}>F{e}^{2+}$
3. $C{r}^{2+}>V^{2+}>R{u}^{3+}>F{e}^{2+}$
4. $V^{2+}>R{u}^{3+}>C{r}^{2+}>F{e}^{2+}$

Q. Magnetic moment of $C{r}^{+2}(Z=24),M{n}^{+2}$ (Z=25) and $F{e}^{2+}(Z=26)$ are $x,y,z$ They are in order :

1. $x<y<z$
2. $x>y>z$
3. $z<x=y$
4. $x=z<y$

Q. The no. of unpaired electrons present in the complex, $\left[Fe\right(CO{)}_5]$ is

1. zero
2. 2
3. 4
4. 3

Q. Which among the following metal carbonyls are diamagnetic inner orbital complexes?
$\left(I\right)Ni(CO{)}_4$
$\left(II\right)Fe(CO{)}_5$
$\left(III\right)V(CO{)}_6$
$\left(IV\right)Cr(CO{)}_6$
Select the correct answer from the codes given below:

1. I and II only
2. II, III and IV only
3. II and IV only
4. I, II and IV only

Q. Among $Ni(CO{)}_4,[Ni\left(CN{)}_4{]}^{2-}and\right[NiC{l}_4^{2-}]$
[IIT-JEE, 1991]

1. $Ni(CO{)}_4$ and $NiC{l}_4^{2-}$ are diamagnetic and $\left[Ni\right(CN{)}_4{]}^{2-}$ is paramagnetic.
2. $NiC{l}_4^{2-}$ and $\left[Ni\right(CN{)}_4{]}^{2-}$ are diamagnetic and $Ni(CO{)}_4$ is paramagnetic.
3. $Ni(CO{)}_4$ and $\left[Ni\right(CN{)}_4{]}^{2-}$ are diamagnetic and $NiC{l}_4^{2-}$ is paramagnetic.
4. $Ni(CO{)}_4$ is diamagnetic and $NiCl{4}^{2-}$ and $\left[Ni\right(CN{)}_4{]}^{2-}$ are paramagnetic.

Q. A compound of vanadium has a magnetic moment $\left(\mu \right)$ of $1.73BM$. If the vanadium ion in the compound is present as $V^{x+}$, then the value of $x$ is ?

Q. The complex $\left[Fe\right(H_{2}O{)}_{5}NO{]}^{2+}$ is formed in the brown ring test for nitrates when freshly prepared $FeS{O}_4$ solution is added to aqueous solution of $N{O}_3^{-}$ followed by addition of concentrated $H_{2}S{O}_4$. Select correct statements about this complex:

1. Color change is due to charge transfer
2. It has iron in $+1$ oxidation state and nitrosyl as $N{O}^{+}$
3. It has magnetic moment of $3.87\text{B.M.}$ confirming three unpaired electrons in $Fe$
4. In complex $Fe$ has $d^{2}s{p}^3$ hybridization
   

Q. The calculated spin only magnetic moment of $C{r}^{2+}$ is :

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1. $5.92BM$
2. $4.90BM$
3. $2.84BM$
4. $3.87BM$

Q. The pair in which both the complexes have the same magnetic moment (spin only value) is:

1. $\left[Cr\right(H_{2}O{)}_6{]}^{2+},[CoC{l}_4{]}^{2-}$
2. $\left[Cr\right(H_{2}O{)}_6{]}^{2+},\left[Fe\right(H_{2}O{)}_6{]}^{2+}$
3. $\left[Mn\right(H_{2}O{)}_6{]}^{2+},\left[Cr\right(H_{2}O{)}_6{]}^{2+}$
4. $[CoC{l}_4{]}^{2-},[Fe(H_{2}O{)}_6{]}^{2+}$

Q.

Hexafluoroferrate (III) ion is an outer orbital complex. The number of unpaired electrons present in Fe is

1. 1

2. 5

3. 4

4. None of these

Q. Which among the following metal carbonyls are diamagnetic inner orbital complexes?
$\left(I\right)Ni(CO{)}_4$
$\left(II\right)Fe(CO{)}_5$
$\left(III\right)V(CO{)}_6$
$\left(IV\right)Cr(CO{)}_6$
Select the correct answer from the codes given below:

1. I and II only
2. II, III and IV only
3. II and IV only
4. I, II and IV only

Q. Which one of the following cyano complexes would exhibit the lowest value of paramagnetic behavior?

1. $\left[Co\right(CN{)}_6{]}^{3-}$
2. $\left[Fe\right(CN{)}_6{]}^{3-}$
3. $\left[Mn\right(CN{)}_6{]}^{3-}$
4. $\left[Cr\right(CN{)}_6{]}^{3-}$

Q. Among the following ions, which one has the highest paramagnetism?

1. $\left[Cr\right(H_{2}O{)}_6{]}^{3+}$
2. $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$
3. $\left[Cu\right(H_{2}O{)}_6{]}^{2+}$
4. $\left[Zn\right(H_{2}O{)}_6{]}^{2+}$

Q. Among $\left[Ni\right(CO{)}_4]$, $[NiC{l}_4{]}^{2-}$, $\left[Co\right(N{H}_3{)}_{4}C{l}_2]Cl$, $N{a}_3\left[Co{F}_6\right]$, $N{a}_2{O}_2$ and $Cs{O}_2$, the total number of paramagnetic compounds are:

1. 2
2. 3
3. 4
4. 5

Q. Among the following ions which has highest paramagnetism

1. $\left[Cr\right(H_{2}O){]}^{3+}$
2. $\left[Fe\right(H_{2}O{)}_6{]}^{2+}$
3. $\left[Cu\right(H_{2}O{)}_6{]}^{2+}$
4. $\left[Zn\right(H_{2}O{)}_6{]}^{2+}$