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Chemistry NEET Questions — Free MCQ Practice

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All the following complex ions are found to be paramagnetic

$P : {[{FeF}_{6}]}^{3 -}; Q : {[{COF}_{6}]}^{3 -}; R : {[V {(H_{2} O)}_{6}]}^{3 +}; S : {[Ti {(H_{2} O)}_{6}]}^{3 +}$

The correct order of their paramagnetic moment (spin only) is

A.

P>Q>R>S

B.

P<Q<R<S

C.

P=Q=R=S

D.

P>R>Q>S

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Explanation

$(A) (P) \to {Fe}^{3 +}, n = 5; (Q) \to {CO}^{3 +}, n = 4 (R) \to V^{3 +}, n = 2; (S) \to {Ti}^{3 +}, n = 1$

n=no. of unpaired electrons.

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Among $[{NiCl}_{2} {({PPh}_{3})}_{2}], [Ni {(HDMG)}_{2}] and [Ni {(CO)}_{4}]$ complexes the hybridisation states of Ni atom are respectively.

A.

${sp}^{3}, {sp}^{3}, {dsp}^{2}$

B.

${sp}^{3}, {dsp}^{2}, {sp}^{3}$

C.

${dsp}^{2}, {dsp}^{2}, {sp}^{3}$

D.

${sp}^{3}, {dsp}^{2}, {dsp}^{2}$

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Amongst ${[Co {(ox)}_{3}]}^{3 -}, {[{CoF}_{6}]}^{3 -} and {[Co ({NH}_{3}) 6]}^{3 +}$

A.

${[Co {(ox)}_{3}]}^{3 -} and {[{CoF}_{6}]}^{3 -}$ are paramagnetic $and {[Co {({NH}_{3})}_{6}]}^{3 +}$ is diamagnetic.

B.

${[Co {(ox)}_{3}]}^{3 -} and {[Co {({NH}_{3})}_{6}]}^{3 +}$ are paramagnetic $and {[{CoF}_{6}]}^{3 -}$ is diamagnetic.

C.

${[Co {(ox)}_{3}]}^{3 -} and {[Co {({NH}_{3})}_{6}]}^{3 +}$ are diamagnetic $and {[{CoF}_{6}]}^{3}$ is paramagnetic.

D.

${[Co {({NH}_{3})}_{6}]}^{3 +}$ $and {[{CoF}_{6}]}^{3 -}$ are paramagnetic $and {[Co {(ox)}_{3}]}^{3 +}$ is diamagnetic.

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All the following complexes show decrease in their weights when placed in a magnetic balance then the group of complexes having tetrahedral geometry is :

(i) $Ni {(CO)}_{4}$ (ii) $K [{AgF}_{4}]$ (iii) ${Na}_{2} [Zn {(CN)}_{4}]$ (iv) $K_{2} [{PlCl}_{4}]$ (V) $[RhCl {({PPh}_{3})}_{3}]$

A.

(ii), (iii) and (v)

B.

(i), (ii) and (iii)

C.

(i), (iii) and (iv)

D.

None of these

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Explanation

(D)

$Ni {(CO)}_{4} - {sp}^{3} (Co strong field ligand); {[{AgF}_{4}]}^{-} - {dsp}^{2} (4 d^{18} electron configuration) {[Zn {(CN)}_{4}]}^{2} - {sp}^{3} (3 d^{10} electron configuration); {[{PtCl}_{4}]}^{2 -} - {dsp}^{2} (5 d^{8} electron configuration) [RhCl {({PPh}_{3})}_{3}] - {dsp}^{2} (4 d^{8} electron configuration) all complexes are diamagnetic in nature in which show decrease in their weights in magnetic field .$

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The 'brown ring' formed at the junction of two layers in the test of nitrate is due to the formation of a complex ion, ${[Fe {(H_{2} O)}_{5} NO]}^{2 +} .$ Which of the following statemens are correct for this complex [u=3.87 B.M.)

(i) Oxidation state of Fe is +1 and NO exists as ${NO}^{+} .$

(ii) The complex ion is in octahedral geometry as attained by ${sp}^{3} d^{2}$ hybridisation.

(iii) The complex is paramagnetic and has three unpaired electrons due to transfer of electron from NO to ${Fe}^{2 +} .$

(iv) The complex is in octahedral geometry as attained by $d^{2} {sp}^{3}$ hybridisation.

(v) The brown colour of the complex is attributed to d-d transition of electron.

A.

(i), (ii) and (v)

B.

(iii), (iv) and (v)

C.

(i), (ii) and (iii)

D.

(ii), (iii) and (v)

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Which of the following statements is most likely to be incorrect ?

A.

$Ti {({NO}_{3})}_{4}$ is a colourless compound

B.

${[Cu {({NCCH}_{3})}_{4}]}^{+} {BF}_{4}^{-}$ is a colourless compound

C.

${[Cr {({NH}_{3})}_{6}]}^{3 +} 3 {Cl}^{‐}$ is a coloured compound.

D.

$K_{3} [{VF}_{6}]$ is a colourless compound

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Explanation

(D)

$(A) {}_{22}{Ti}_{4 +} E . C = 3 d ° 4 s ° colourless (B) {}_{29}{Cu}_{+} E . C = 3 d^{10} 4 s ° colourless (C) {}_{24}{Cr}_{3 +} E . C = 3 d^{3} 4 s ° coloured (most likely) (D) {}_{23}V_{3 +} E . C = 3 d^{2} 4 s ° coloured (most likely)$

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Identify the correct order of wavelength of light absorbed for the following complex ions.

${[Co {(H_{2} O)}_{6}]}^{3 +;}$ ${[Co {(CN)}_{6}]}^{3 -;}$ ${[Co {(I)}_{6}]}^{3 -;}$ ${[Co {(en)}_{3}]}^{3 +}$

I II III IV

A.

III>I>IV>II

B.

II>IV>I>III

C.

III>I>II>IV

D.

I>III>IV>II

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Explanation

(A)

$∆$ corresponds to the wave length of the visible light and $∆ = \frac{hc}{λ}$

The order of ability to produce d-orbital spliting of various ligands ;

$CO > {CN}^{-} > {NO}_{2}^{-} > en > {NH}_{3} > H_{2} O > {OH}^{-} > F^{-} > {Cl}^{-} > {Br}^{-} > I^{-}$

$\begin{matrix} storng field \\ ligands \\ (larger ∆) \end{matrix}$ $\begin{matrix} weak field \\ ligands \\ (smaller ∆) \end{matrix}$

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The total number of isomers of the complex, $[Co {({NH}_{3})}_{3} {({NO}_{2})}_{2} ({NO}_{3})]$ complex is :

A.

10

B.

6

C.

4

D.

12

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Explanation

It shows geometrical, ionisation and linkage isomers.

${NO}_{2} - {NO}_{2} cis ‐ trans . {NO}_{2} - ONO cis ‐ trans . ONO - ONO cis ‐ trans . {NO}_{2} - {NO}_{3} cis ‐ trans . ONO - {NO}_{3} cis ‐ trans . ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Total number of isomers = 10 .$

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Which one of the following complexes exhibit chirality ?

A.

${[Cr {(ox)}_{3}]}^{3}$

B.

$cis - [{PtCl}_{2} (en)]$

C.

$cis - {[{RhCl}_{2} {({NH}_{3})}_{2}]}^{‐}$

D.

$mer - [Co {({NO}_{2})}_{3} (trine)]$

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Explanation

(A)

(A) has three symmetrical bidentate ligands, which lack plane of symmetry.

(B) and (C) has square planar geometry and has plane of symmetur.

(D) has one of the plane of symmetur. So (B), (C) and (D) will not show chirality.

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Which of the following has both fac-mer and optical isomers?

A.

$[Co {({NH}_{3})}_{5} {({NO}_{3})}_{}]$

B.

${[Co {(e n)}_{3}]}^{3 -}$

C.

$[Co {(gly)}_{3}]$

D.

none of these

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