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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 NH3 to give an explosive compound C. The compounds A, B and C are:
  • A=MnO2,B=Cl2,C=NCl3
  • A=MnO,B=Cl2,C=NH4Cl
  • A=Mn3O4,B=Cl2,C=NCl3
  • A=MnO3,B=Cl2,C=NCl2
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(NH3)6]3+
  • [Cr(NH3)6]3+
  • [Co(NH3)6]3+
  • [Zn(NH3)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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