MCQ Questions for Class 12 Engineering Chemistry The D-And F-Block Elements Quiz 2

The adsorption of hydrogen by platinum black is called :

0%
hydrogenation
0%
Reduction
0%
Occlusion
0%
Hydration

Transition metals show paramagnetism

0%
due to characteristic configuration
0%
high lattice energy
0%
due to variable oxidation states
0%
due to unpaired electrons

Among the following metals, interatomic forces are probably the weakest in :

0%
$Cu$
0%
$Ag$
0%
$Zn$
0%
$Hg$

Explanation

Among the metals, interatomic forces are probably the weakest in

$Hg.$

This can be understand from the fact that

$Hg$ is liquid whereas

$Cu, Ag$ and

$Zn$ are solids at room temperature.

Among the following which exhibits hydrogen, covalent, and coordinate bonding?

0%
$MnSO_4 . 4H_2 O$
0%
$CuSO_4 . 5H_2 O$
0%
$FeSO_4 . 6H_2 O$
0%
$FeSO_4. 5H_2 O$

Explanation

$CuSO_4$ exhibit coordinate, covalent and hydrogen bonding.

Hence, Option "B" is the correct answer.

1669767_1759870_ans_c8504bd9673441b9b736038c15e0a3aa.jfif

The approximate size of the nucleus of

$_{28}^{64}Ni$ is:

0%
3 fm
0%
4 fm
0%
5 fm
0%
2 fm

Explanation

Approximate size of the nucleus is given by,

$R_A=1.25 \times {A}^{\frac{1}{3}} fm$ , for this given nucleus

$A=64$ , and

$Z=28$ ,

Therefore size of this nucleus,

$R_{64}=1.25 \times {64}^{\frac{1}{3}} fm=5.0 fm$

So, option 'C' is correct.

${Cr_{2}O_{7}}^{2-}$ ion, the maximum number of bonds having the same Cr - O bond length is :

0%
5
0%
4
0%
6
0%
3

Explanation

$Cr_{2}O_{7}^{2-}$ ion, 6

$(Cr - O)$ bonds have the same bond length 163 pm because of the resonance and 2

$(Cr - O)$ bonds have a bond length of 179 pm.

Match the List

$I$ with List

$II$ and List

$III$

List $I$	List $II$	List $III$
a. Reduction	i. Adam's catalyst	$TiCl_4$
b. Polythene production	ii. Wacker process	$Pt$
c. Aldehyde manufacture	iii. Natta catalyst	$PbCl_2$

0%
$a\to i \to 2$
0%
$b\to ii \to 1$
0%
$c\to iii\to 3$
0%
none

Which among the following ions has maximum value of magnetic moment?

0%
$Cu^{2+}$
0%
$Mn^{2+}$
0%
$Cr^{2+}$
0%
$Ti^{2+}$

Which of the following ions is paramagnetic?

0%
$Cu^+$
0%
$Zn^{2+}$
0%
$Ti^{3+}$
0%
$Ti^{4+}$

Explanation

$Ti^{+3}$ is paramagnetic due to presence of an unpaired electron.

$Ti\to [Ar]3d^24s^2$

$Ti^{3+}\to [Ar]3d^14s^0$

1654449_1758867_ans_a726adb829a54c79ab0ac46c6ce55701.png

The dark red colour of bombs in fireworks is due to the presence of

0%
$Na$
0%
$Ba$
0%
$Sr$
0%
$K$

Which ion has maximum magnetic moment?

0%
$V^{3+}$
0%
$Mn^{3+}$
0%
$Fe^{3+}$
0%
$Cu^{2+}$

Explanation

$Fe^{3+}$ ion has maximum magnetic moment as it has highest (5) number of unpaired electrons.

Chromate and dichromate ions are:

0%
$CrO_{4}^{2-}$ and $Cr_{2} O_{7}^{2-}$
0%
$Cr_{2} O_{7}^{2-}$ and $CrO_{4}^{2-}$
0%
$CrO_{4}^{2-}$ and $Cr_{2}O_{5}^{2-}$
0%
$Cr_{2}O_{5}^{2-}$ and $CrO_{4}^{2-}$

Explanation

(i) Chromate ion

$\longrightarrow CrO_4^{2-}$

(Refer to Image 1)

One chromium atom combined to

$4$ oxygen atom.

(ii) Dichromate ion

$\longrightarrow Cr_2O_7^{2-}$

(Refer to Image 2)

Two chromium and

$7$ oxygen atom.

1064891_513337_ans_26a84786251045abb5febc419c189bd2.png

Which one of the following shows highest magnetic moment?

0%
${Fe}^{2+}$
0%
$C{o}^{2+}$
0%
${Cr}^{3+}$
0%
${Ni}^{2+}$

Explanation

Highest magnetic moment is shown by the ion having maximum number of unpaired electron which if in the case of

$Fe^{2+}$ having 4 unpaired electrons in the electronic configuration.

Which one of the following elements forms compounds that are all coloured?

0%
Magnesium
0%
Aluminium
0%
Iron
0%
Chromium

Which of the following statements is not correct about magnetic behaviour of substances?

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Diamagnetic substances are repelled by an applied magnetic field.
0%
Paramagnetic substances are attracted by an applied magnetic field.
0%
Magnetic moment of n unpaired electrons is given by $\mu=\sqrt n(n-2)$ B.M.
0%
Magnetic moment increases as the number of unpaired electrons increases.

Explanation

Diamasnetic substances are repelled by an applied magnetic field.[since,it has no unpaired electrons]

paramagnetic substances,due to presence of unpaired free electrons in them,are attracted by an applied magnetic field.

Magnetic moment of nunpaired electrons is given by the formula,magnetic moment

$\mu=\sqrt{n(n+2)}$ .

Which of the following complexes is diamagnetic?

0%
$Ni(CO)_4$
0%
$Ni(Cl_4)^{2-}$
0%
$Ni(Br)_4^{2-}$
0%
$NiCl_2.4H_2O$

Explanation

$CO$ is a strong ligand so induce pairing of electrons and hence

$Ni(CO)_4$ is diamagnetic.

$Ni(CO)_4\to Ni^0\to [Ar]3d^84s^2$

In the presence of strong field ligand pairing of electrons take place.

$Ni^0\to [Ar]3d^{10}4s^0\to$ so electrons of ligand will occupy 4s and 4p electrons.

So, there is no unpaired electrons making it diamagnetic.

A solution when treated with dimethyl glyoxime and

$NH_4OH$ gives a rose red complex. The metal present is

0%
$Ni$
0%
$V$
0%
$Co$
0%
$Mn$

Explanation

The solution must contain

$Ni^{2+}$ as it forms a complex with dimethyl glyoxime

$(DMG)$ giving

$[Ni(DMG)_2]$ which is rose-red in colour.

Which of the following has diamagnetic character?

0%
$[ NiCl_4]^{2-}$
0%
$[ CoF_6]^{3-}$
0%
$[Fe(H_2O)_6 ]^{2+}$
0%
$[Ni (CN)_4]^{2-}$

Explanation

$[ Ni(CN)_4]^{2-} \to Ni^{2+}\to [Ar]3d^8.$ The pairing of electrons will take place as

$CN^-$ is strong field ligand.

$[ Ni(CN)_4]^{2-}$ has no unpaired electron. It is diamagnetic.

1664252_1760070_ans_f845e5f32a59470db357f0e8e800a497.png

Wilkinson's catalyst used as a homogeneous catalyst in the hydrogenation of alkaline contains

0%
Iron
0%
Aluminium
0%
Rhodium
0%
Cobalt

Explanation

Wilkinson's catalyst is Chlorotris(triphenylphosphine)rhodium(I)

$([Rh(PPh_3)_3Cl])$ . It contains Rh as the central metal atom.

Reagent (E) is:

0%
$LAH$
0%
$NaBH_4$
0%
$H_2 / Ni$
0%
$K + liq. NH_3$ in $EtOH$

Ziegler-Natta catalysts

0%
Are triethyl aluminium titanium tetrachloride complex $(C_2H_3)Al + TiCl_4.$
0%
Are used to prepare stereospecific addition polymers
0%
Are employed to have stereochemical control of the polymerisation process.
0%
All the above

Which of the following paramagnetic ions would exhibit magnetic moment (Spin only) of the order 5 BM? (Atomic number Mn = 25, Cr = 24, V = 23, Ti = 22)

0%
$V^{2+}$
0%
$Ti^{2+}$
0%
$Mn^{+2}$
0%
$Cr^{2+}$

Explanation

Configuration of ,

$V^{2+}[Ar]4s^03d^3$

$n=3$

$Ti^{2+}[Ar]4s^03d^2$

$n=2$

$Mn^{2+}[Ar]4s^03d^5$

$n=5$

$Cr^{2+}[Ar]4s^03d^4$

$n=4$

Hence spin moment of

$Cr^{2+}=\sqrt{4(4+2)}\simeq4.92BN\simeq5BM$

The ratio of number of exchange pairs present in

$d^{9}$ and magnetic moment of Cr in B.M. is:-

0%
$\frac{2}{\sqrt{3}}$
0%
$\frac{2\sqrt{3}}{3}$
0%
$\frac{2\sqrt{3}}{4}$
0%
$\frac{16}{\sqrt{35}}$

Explanation

Magnetic moment of

$Cr$ in

$d^9$ :

$\mu=\sqrt {n(n+2)}$

$=\sqrt {1(1+2)}=\sqrt {3}$ (Refer to Image)

Two exchange pairs present in

$d^9$ of

$Cr$ :

$\therefore \cfrac {2}{\sqrt {3}}$ .

1220167_1115473_ans_f7dfb0e42413480fa0ffd83a797c128e.JPG

Which of the following can convert acidified

${ Cr }_{ 2 }{ O }_{ 7 }{^{2-}}$ to green product?

0%
${ SO }_{ 2 },{ H }_{ 2 }{ SO }_{ 3 }$ and ${ H }_{ 2 }{ SO }_{ 4 }$
0%
${ SO }_{ 2 },{ H }_{ 2 }{ S }_{ }$ and ${ H }_{ 2 }{ SO }_{ 3 }$
0%
${ SO }_{ 3 },{ H }_{ 2 }{ S }$ and ${ Fe }^{ 3+ }$
0%
${ SO }_{ 3 }^{ - },{ H }_{ 2 }S$ and ${ Fe }^{ +2 }$

Explanation

Experimental verification for the presence of sulphur dioxide

$\left( { SO }_{ 2 } \right)$ gas

${ K }_{ 2 }{ Cr }_{ 2 }{ O }_{ 7 }+{ H }_{ 2 }{ SO }_{ 4 }+3{ SO }_{ 2 }\rightarrow { K }_{ 2 }{ SO }_{ 4 }+{ Cr }_{ 2 }{ \left( { SO }_{ 4 } \right) }_{ 3 }+{ H }_{ 2 }O$

Orange-coloured-dichromate solution turns green due to formation of chromium (III) sulphate.

Amongst the following ions, which is considered as most stable in

${ M }^{ 2+ }$ state?

0%
${ Ti }^{ 2+ }/Ti\left( -1.63V \right)$
0%
${ V }^{ 2+ }/V\left( -1.11V \right)$
0%
${ Cr }^{ 2+ }/Cr\left( -0.90V \right)$
0%
${ Mn }^{ 2+ }/Mn\left( 1.18V \right)$

Explanation

Half reactions with lowest standard reduction have stable reactants (ions).
Here,

$Ti^{2+}+2e^-\longrightarrow Ti\ [Reduction]$
The standard reduction potential of this reaction is least. So, the reactant

$Ti^{2+}$ is more stable.

The pair having similar magnetic moment is:

0%
$Ti^{3+},V^{3+}$
0%
$Cr^{3+},Mn^{3+}$
0%
$Mn^{2+},Fe^{3+}$
0%
$Ti^{2+},Mn^{2+}$

Atomic number of three elements A, B, and C are respectively,

$Pm\ (Z=61),\ Sm\ (Z=62),\ Eu\ (Z=63).$

Which one has a maximum atomic radius?

0%
A
0%
B
0%
C
0%
All have the same radius

Which of the following pairs of atom have the most similar radii ?

0%
$Zr, Hf$
0%
$Cu, Ag$
0%
$Sc, Ti$
0%
$Pd, Pt$

Which of the following will be paramagnetic?

0%
$O_{2}^{2-}$
0%
$Cr^{3+}$
0%
$Na^{+}$
0%
$Cu^{+}$

Explanation

Configuration of $Cr^{3+}$ is: $[Ar]3d^3$
Since there are five-3d orbitals, they are not all at least singly filled yet, and thus, all three electrons in the lowest-energy configuration are unpaired. So, this is paramagnetic.

Which of the following factors may be regarded as the main cause of lanthanide contraction?

0%
Poor shielding of one of 4f electron by another in the subshell
0%
Effective shielding of one of 4f electrons by another in the subshell.
0%
Poorer shielding of 5d electrons by 4f electrons
0%
Greater shielding of 5d electrons by 4f electrons

Explanation

Lanthanoid contraction is due to poor sheilding effect of one of

$4f$ electron by another in the subshell.

Which of the following ions in its aqueous solution possesses the value of magnetic moment as

$3.87$ ?

0%
$Cu^{2+}$
0%
$Cu^{3+}$
0%
$Co^{3+}$
0%
$Fe^{3+}$

Which of the following ion will give colourless aqueous solution ?

0%
$Ni^{2+}$
0%
$Sc^{3+}$
0%
$Cu^{2+}$
0%
$Mn^{3+}$

Explanation

Solution:- (B)

${Sc}^{+3}$

Only the ions that have electrons in

$d$ -orbital and in which

$d-d$ transition is possible will be coloured.

Electronic configuration of

${Sc}^{+3} \left( \text{At. no. = 21} \right) - 1 {s}^{2} 2 {s}^{2} 2{p}^{6} 3{s}^{2} 3 {p}^{6}$

Since it do not contains electrons in

$d$ -orbital and hence will not undergo

$d-d$ transition and do not show colour.

Transition metals are good electrical conductor because ___________.

0%
they are metals
0%
they are solids
0%
they have free electrons in outer energy levels
0%
they are hard

Transition metals are often para magnetic owing to ____________.

0%
high melting point and boiling point
0%
the presence of vacant orbitals
0%
the presence of unpaired electrons
0%
malleability and ductility

Wilkinson's catalyst is :

0%
$TiCl_4$ and $Al(C_2H_5)_3$
0%
$[(Ph_3P)_3RhCl]$
0%
$TiCl_4$ and $(C_6H_5)_3P$
0%
$none\ of\ these$

Among the following, the lowest degree of paramagnetism per mole of the compound will be shown by:

0%
$MnSO_4. 4H_2O$
0%
$CuSO_4. 5H_2O$
0%
$FeSO_4. 7H_2O$
0%
$NiSO_4. 6H_2O$

Which is a coloured ion?

0%
$[Cr(H_2O)_6]^{3+}$
0%
$[Cu(CN)_4]^{3-}$
0%
$[Ti(H_2O)_6]^{4+}$
0%
$[Sc(H_2O)_6]^{3+}$

$3d$ series, the maximum magnetic moment is shown by:

0%
$Sc (At\ no.\ 21)$
0%
$V(23)$
0%
$Cr(24)$
0%
$Fe(26)$

Select the correct statement:

0%
Colour of the transition metal ion arises due to $d-d$ transition
0%
Colour certain oxysalts of transition metals is due to charge transfer
0%
Both are correct
0%
None is correct

$Fe^{2+}$ does not give prussian blue colour with

$Fe^{2+}$ , but on its reaction with (x), prussian blue colur appears with the reagent (x) is

0%
$MnO_{4}-/H^{+}$
0%
$H_{2}SO_{4}$
0%
$NH_{3}$
0%
All true

Which amongst the following metal carbonyls are inner orbital complexes with diamagnetic property?

0%
$Ni(CO)_{4}$
0%
$Fe(CO)_{5}$
0%
$V(CO)_{6}$
0%
$Cr(CO)_{6}$

Which of the following ions gives coloured solution?

0%
$Cu^+$
0%
$Zn^{2+}$
0%
$Ag^+$
0%
$Fe^{2+}$

Explanation

$Fe^{2+}$ ion is coloured due to presence of 4 unpaired electrons in d-orbitals.

Which one of the following statements about lanthanides is false ?

0%
Lanthanides are seperated from one another by ion exchange method
0%
The ionic radii of trivalent lanthanides steadily increases with increase in atomic number
0%
All lanthanides are highly dense metals
0%
Most typical oxidation state of lanthanides is +3

What would be magnetic moment of

$Gd^{+3}$ (

$Z = 64$ )?

0%
7.9 BM
0%
3.62 BM
0%
10.60 BM
0%
9.72 BM

Explanation

Electronic configuration of

$[Gd]^{3+}:[Xe]4f^{7}$

Hence number of unpaired electron

$n=7$

Hence,

$magnetic \ moment=\sqrt{n(n+2)}=\sqrt{63}=7.9BM$

The position in the periodic table to which

$Fe$ and

$Zn$ elements belong to __________ .

0%
Alkali metal
0%
Alkaline earth metal
0%
d-block
0%
None of these

Explanation

$Fe$ and

$Zn$ elements belong to d-block because the valence electron enters into the d-orbital.

Hence option C is correct.

The catalytic activity of the transition metals and their compounds is described to their

0%
chemical reactivity
0%
magnetic behaviour
0%
unfilled d-orbitals
0%
ability to adopt multiple oxidation states and their complexing ability

The transition metal used as a catalyst is:

0%
Nickel
0%
Platinum
0%
Cobalt
0%
All of these

Explanation

$Ni$ ,

$Pt$ and

$Co$ all three transition metals are used as a catalysts.

Option D is correct.

Which of the following transition metal is used as a catalyst?

0%
Nickel
0%
Cobalt
0%
Gold
0%
Both (A) and (B)

Which of the following will show increase in weight when kept in magnetic field?

0%
$TiO_2$
0%
$Fe_2(SO_4)_3$
0%
$KMnO_4$
0%
$ScCl_3$

Explanation

$Fe_2(SO_4)_3 \to Fe^{3+} -[Ar]3d^5 - 5$ electrons are unpaired. So, Fe will be attracted in the magnetic field so it will show an increase in weight.

$V_2O_5$ is useful as catalyst in

0%
manufacturing of $H_2SO_4$
0%
manufacturing of $HNO_3$
0%
manufacturing of $Na_2CO_3$
0%
it is not a catalyst

Explanation

$V_2O_5$ is useful as catalyst in manufacturing of

$H_2SO_4$

Hene, Option "A" is the correct answer.

CBSE Questions for Class 12 Engineering Chemistry The D-And F-Block Elements Quiz 2 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Engineering Chemistry The D-And F-Block Elements Quiz 2 - MCQExams.com

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Practice Class 12 Engineering Chemistry Quiz Questions and Answers

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