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

When a brown compound of Mn(A) is treated with $$HCl$$, it gives a gas B. The gas B taken in excess reacts with $$NH_3$$ to give an explosive compound C. The compounds A, B and C are:
  • $$A=MnO_2, B=Cl_2, C=NCl_3$$
  • $$A=MnO, B=Cl_2, C=NH_4Cl$$
  • $$A=Mn_3O_4, B=Cl_2, C=NCl_3$$
  • $$A=MnO_3, B=Cl_2, C=NCl_2$$
In a transition series, with the increase in atomic-number, the paramagnetism :
  • increases gradually
  • decreases gradually
  • first increases to a maximum and then decreases
  • first decreases to a minimum and then increases
Which of the following complex compounds will exhibit the highest paramagnetic behaviour?

$$[At. no. Ti = 22, Cr = 24, Co = 27, Zn = 30]$$
  • $$[Ti(NH_{3})_{6}]^{3+}$$
  • $$[Cr(NH_{3})_{6}]^{3+}$$
  • $$[Co(NH_{3})_{6}]^{3+}$$
  • $$[Zn(NH_{3})_{6}]^{2+}$$
The magnetic moment of $$\left[ Co{ \left( N{ H }_{ 3 } \right)  }_{ 6 } \right] { Cl }_{ 3 }$$ is:
  • $$1.73$$
  • $$2.83$$
  • $$6.6$$
  • Zero
Actinides exhibit a larger number of oxidation state than that of corresponding lanthanides. The reason behind this aspect is :
  • lesser energy difference between 5f and 6d-orbitals than between 4f and 5d-orbitals
  • larger atomic size of actinides than the lanthanides
  • more energy difference between 5f and 6d orbitals than between 4f and 5d-orbitals
  • greater reactive nature of the actinides than the lanthanides
If a transition-metal compound absorbs violet-indigo radiation in the visible region. Its color would be?
  • Green
  • Yellow
  • Orange
  • Blue
When dil. $${ H }_{ 2 }S{ O }_{ 4 }$$ is added to aqueous solution of potassium chromate, yellow colour of solution turns to orange colour. It indicates :
  • chromate ions are reduced
  • chromate ions are oxidized
  • mono-centric complex is converted into dicentric complex
  • oxygen gets removed from chromate ions
In the dichromate dianion, the nature of bonds are:
  • four equivalent $$Cr - O$$ bonds
  • six equivalent $$Cr - O$$ bonds and one $$O - O$$ bond
  • six equivalent $$Cr - O$$ bonds and one $$Cr - Cr$$ bond
  • six non-equivalent $$Cr - O$$ bonds
  • six equivalent $$Cr - O$$ bonds and one $$Cr - O - Cr$$ bond
The colour of $$Cu{ Cr }_{ 2 }{ O }_{ 7 }$$ solution in water is green because__________.
  • $${ Cu }^{ 2+ }$$ ion is green
  • $${ Cr }_{ 2 }{ O }_{ 7 }^{ 2- }$$
  • both the ions are green
  • $${ Cu }^{ 2+ }$$ ion is blue and $${ Cr }_{ 2 }{ O }_{ 7 }^{ 2- }$$ ion is yellow
The magnetic moment of a transition metal ion is $$\sqrt { 15 } BM$$. Therefore, the number of unpaired electrons present in it is:
  • $$4$$
  • $$1$$
  • $$2$$
  • $$3$$
Which one of the following complex ions has the highest magnetic moment?
  • $$[Cr(NH_{3})_{6}]^{3+}$$
  • $$[Fe(CN)_{6}]^{3-}$$
  • $$[Fe(CN)_{6}]^{4-}$$
  • $$[Zn(NH_{3})_{6}]^{2+}$$
The magnetic moment of a divalent ion in aqueous solution with atomic number 25 is:
  • 5.47 B.M
  • 2.9 B.M
  • 6.9 B.M
  • 6.7 B.M
A transition metal $$X$$ has a configuration $$\left[Ar\right]3d^{5}$$ in its $$+3$$ oxidation state. Its atomic number is:-
  • $$22$$
  • $$26$$
  • $$28$$
  • $$19$$
Magnetic moments of $$V(Z = 23), Cr(Z = 24)$$ and $$Cu(Z = 29)$$ are x,y and z respectively, then which of the following is correct?
  • $$x = y = z$$
  • $$y > x > z$$
  • $$x > y > z$$
  • $$z > y > x$$
Which of the following ion will not form coloured aqueous solution?
  • $$Ni^{2+}$$
  • $$Fe^{3+}$$
  • $$Ti^{4+}$$
  • $$Cu^{2+}$$
(i) $$\underset{aq. suspension}{BaCO_3}+Na_2CrO_4+AcOH\rightarrow \underset{ppt}{M}$$
(ii) $$\underset{aq. suspension}{BaCO_3}+Na_2CrO_4+HCN\rightarrow \underset{ppt.}{N}$$
Which is the correct option regarding the given reactions?
  • M and N are the same and characterized as $$BaCrO_4$$
  • M is $$BaCrO_4$$ and N stands for no precipitate
  • M is $$BaCrO_4$$ and N is $$BaCO_3$$
  • M stands for no precipitate and N is $$BaCrO_4$$
Identify the oxidation states of titanium $$(Z=22)$$ and copper $$(Z=29)$$ in their colourless compounds:
  • $$Ti^{3+}, Cu^{2+}$$
  • $$Ti^{2+}, Cu^{2+}$$
  • $$Ti^{4+}, Cu^{+}$$
  • $$Ti^{4+}, Cu^{2+}$$
Which one of the following shows maximum paramagnetic character?
  • $${ \left[ Fe{ \left( CN \right) }_{ 6 } \right] }^{ 3- }$$
  • $${ \left[ Fe{ \left( CN \right) }_{ 6 } \right] }^{ 4- }$$
  • $${ \left[ Cr{ \left( { H }_{ 2 }O \right) }_{ 6 } \right] }^{ 3+ }$$
  • $${ \left[ Cu{ \left( { H }_{ 2 }O \right) }_{ 6 } \right] }^{ 2+ }$$
The incorrect statement is :
  • $$Cu^{2+}$$ salts give red colour borax bead test in reducing flame.
  • $$Cu^{2+}$$ and $$Ni^{2+}$$ ions give black colour precipitate with $$H_2S$$ in the presence of $$HCl$$ solution.
  • Ferric ion gives blood red colour with potassium thiocyanate.
  • $$Cu^{2+}$$ ion gives chocolate coloured precipitate with potassium ferrocyanide solution.
What would be the correct order if Zn,Fe,Al and Cu are arranged in increasing order of reactivity ?
  • Cu, Fe, Zn, Al
  • Al, Cu, Fe, Zn
  • Zn, Al, Cu, Fe
  • Fe, Zn, Al, Cu
The bonds generally formin compounds of Actinoids are:
  • convalent
  • ionic
  • coordinate covalent
  • metallic
Out of $$TiF_{6}^{2-},\ CoF_{6}^{3-},\ Cu_{2}Cl_{2}$$ and $$NiCl_{4}^{2-}$$, the colourless sphere are..... 
  • $$Cu_{2}Cl_{2},\ NiCl_{4}^{2-}$$
  • $$TiF_{6}^{2-},\ Cu_{2}Cl_{2}$$
  • $$CoF_{6}^{3-},\ NiCl_{4}^{2-}$$
  • $$TiF_{6}^{2-},\ CiF_{6}^{3-}$$
Which one of the following statement is incorrect about transition elements?
  • The last electron enters into them in the d-orbital
  • Their properties are in between those of s-block elements and p-block elements
  • The transition elements with smallest atomic number is scandium
  • Lanthanum is not a transition elements but is a lanthanoid
Select the incorrect match (reason of color):-
  • $$KMnO_{4},K_{2}Cr_{2}O_{7}\Rightarrow $$ charge transfer spectra
  • Halogen $$\Rightarrow $$ HOMO-LUMO transition
  • $$[Ti(NH_{3})_{6}]^{+3}\Rightarrow $$ d-d transition
  • $$CrO_{2}Cl_{2},CrO_{4}^{-2}\Rightarrow $$ d-d transition
$$M^{x+}$$ ion has magnetic moment 2.84 BM.Then 'x' is (Z of M=22)
  • 3
  • 2
  • 5
  • 4
Which of the following set of elements are Ferromagnetic in nature?
  • Zn, Cd and Hg
  • Cu,Ag and Au
  • Fe, Co and Ni
  • Sc, Ti and U
The spin only magnetic moment of $$[Cu(NH_3)_4]^{2+}$$ complex is:-
  • $$\text{1.732 B.M.}$$
  • $$\text{2.2 B.M.}$$
  • $$\text{3.87 B.M.}$$
  • $$\text{5.96 B.M.}$$
Which of the following pair have almost similar size
  • $$Ti_{22}$$ and $$Zr_{40}$$
  • $$Nb_{41}$$ and $$Ta_{73}$$
  • $$Y_{39}$$ and $$La_{57}$$
  • $$Ca_{20}$$ and $$Ir_{31}$$
In $$K_2Cr_2O_7$$, every $$Cr$$ is linked to:
  • Two O-atoms
  • Three O-atoms
  • Four O-atoms
  • Five O-atoms
Find the spin magnetic moment of the $$Fe^{3+}$$.
  • $$5.91$$
  • $$4.89$$
  • $$3.87$$
  • none of these
$$CrO_4^{2-}$$ (yellow) $$\xrightarrow[{pH=Y}]{pH=X}$$ $$Cr_2O_7^{-2}$$ (orange)
The $$pH$$ values $$X$$ and $$Y$$ are respectively:
  • 6, 8
  • 6, 6
  • 8, 5
  • 7, 7
The magnetic moment of $$V(Z= 23), Cr (Z= 34)$$ and $$Mn (Z= 25)$$ are $$x, y, z$$. Hence:
  • $$x = y = z$$
  • $$z < y < x$$
  • $$x < y < z$$
  • $$x < z < y$$
Which of the following ion has magnetic moment 3.87 BM?
  • $$Co^{2+}$$
  • $$Mn^{3+}$$
  • $$Cu^{+}$$
  • $$Ni^{2+}$$
The effect of lanthanoid contration in the lanthanid series of elements by and large means: 
  • decrease in atomic radii and increases in ionic radii
  • decrease in both atomic and ionic radii
  • increase in both atomic and ionic radii
  • increases in atomic radii and decrease in ionic radii
A transition metal cation M$$^{2+}$$ has a magnetic moment $$\sqrt35$$. what is the atomic number of the metal?
  • $$24$$
  • $$25$$
  • $$26$$
  • $$27$$
Orbital angular momentum of $$ e^- $$ (last filled ) in Cr is 
  • Zero
  • $$ \sqrt { 2 } \frac { h }{ 2\pi } $$
  • $$ \sqrt { 6 } \frac { h }{ 2\pi } $$
  • $$ \sqrt { 12 } \frac { h }{ 2\pi } $$
An iron $$ _{25}Mn^{x+} $$ has the magnetic moment of 4.9 BM. What is the value of x ?
  • 3
  • 4
  • 2
  • 5
Which of the following complex is anion ?
  • Fluoro pentaammine cobalt (III)
  • Trioxalato ferrate (III)
  • Penta Carbonyl iron
  • Dichloro diammine platinum(II)
The magnetic moment (spin only) of $$[NiCI_4]^{2-}$$ is:
  • 5.46 BM
  • 2.83 BM
  • 1.41 BM
  • 1.82 BM
The metal ion which is not colored is: 
  • $${ Fe }^{ 3+ }$$
  • $${ V }^{ 2+ }$$
  • $${ Zn }^{ 2+ }$$
  • $${ Ti }^{ 3+ }$$
Which of the following lanthanum ions is diamagnetic?
  • $${ Ce }^{ 4+ }$$
  • $${ Sm }^{ 2+ }$$
  • $$Eu^{ 2+ }$$
  • $$Yb^{ 2+ }$$
Magnetic moment 2.84 B.M is given by:- 
  • $$Ti^{3+}$$
  • $$Cr^{2+}$$
  • $$Co^{2+}$$
  • $$Ni^{2+}$$
Colourless ion is:
  • $${ \left[ { Fe\left( CN \right) }_{ 6 } \right] }^{ -3 }$$
  • $${ \left[ { Ti\left( { H }_{ 2 }O \right) }_{ 6 } \right] }^{ +3 }$$
  • $${ \left[ { Sc\left( { H }_{ 2 }O \right) }_{ 6 } \right] }^{ +3 }$$
  • $${ \left[ { Cu\left( NH_{ 3 } \right) }_{ 4 } \right] }^{ +2 }$$
The correct order of spin -only magnetic moments among the following is :
(Atomic number : $$ Mn =25, Co + 27 , Ni = 28, Zn = 30) $$
  • $$ [ZnCl_4]^{2-} > [NiCl_4]^{2-} > [CoCl_4]^{2-} > [MnCl_4]^{2-} $$
  • $$ [CoCl_4]^{2-} > [MnCl_4]^{2- } > [NiCl_4]^{2-} > [ZnCl_4]^{2-} $$
  • $$ [MnCl_{ 4 }]^{ 2- }>[CoCl_{ 4 }]^{ 2- }>[NiCl_{ 4 }]^{ 2- }>[ZnCl_{ 4 }]^{ 2- } $$
  • $$ [NiCl_{ 4 }]^{ 2- }>[CoCl_{ 4 }]^{ 2- }>[MnCl_{ 4 }]^{ 2- }>[ZnCl_{ 4 }]^{ 2- } $$
An orange solid (A) on heating gave a green residue (B), a colourless gas (C) and water vapour. The gas (C) on passing over heated Mg gave white solid (D) which on reaction with water gave a gas (E). The gas (E) forms white fumes with HCl.
An orange solid A is
  • Sodium dichromate
  • Potassium dichromate
  • Potassium chromate
  • Ammonium dichromate
Fenton reagent is 
  • $${ FeSO }_{ 4 }+{ H }_{ 2 }{ O }_{ 2 }$$
  • $$Zn + HCl$$
  • $$Sn + HCl$$
  • None of the above
The number of unpaired electron(s) in $$ [Fe(H_2O)_6]^{2+} $$ is 
  • 1
  • 2
  • 3
  • 4
Copper sulphate disolves in excess of $$KCN$$ to give:
  • $$Cu\left( CN \right) _{ 2 }$$
  • $$CuCN$$
  • $$[Cu\left( CN \right) _{ 4 }]^{ 3- }$$
  • $$[Cu\left( CN \right) _{ 4 }]^{ 2- }$$
Which of the following ions has maximum magnetic moment?
  • $$Mn^{2+}$$
  • $$Fe^{2+}$$
  • $$V ^ { 3 + }$$
  • $$Ti^{2+}$$
The d-electronic configuration of $${ Cr }^{ 2+ },{ Mn }^{ 2+ },{ Fe }^{ 2+ }$$ and $${ Ni }^{ 2+ }$$ are $${ 3d }^{ 4 },{ 3d }^{ 5 },{ 3d }^{ 6 }$$ and $${ 3d }^{ 8 }$$ respectively. Which one of the following aqua complexes will exhibit the maximum paramagnetic character?
  • $$\left[ \left( Fe\left( { H }_{ 2 }O \right) \right) _{ 6 } \right] ^{ 2+ }$$
  • $$\left[ \left( Ni\left( { H }_{ 2 }O \right) \right) _{ 6 } \right] ^{ 2+ }$$
  • $$\left[ \left( { C }{ r }\left( { H }_{ 2 }O \right) \right) _{ 6 } \right] ^{ 2+ }$$
  • $$\left[ \left( { Mn }\left( { H }_{ 2 }O \right) \right) _{ 6 } \right] ^{ 2+ }$$
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