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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 [Co(NH3)6]Cl3 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. H2SO4 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 CrO bonds
  • six equivalent CrO bonds and one OO bond
  • six equivalent CrO bonds and one CrCr bond
  • six non-equivalent CrO bonds
  • six equivalent CrO bonds and one CrOCr bond
The colour of CuCr2O7 solution in water is green because__________.
  • Cu2+ ion is green
  • Cr2O27
  • both the ions are green
  • Cu2+ ion is blue and Cr2O27 ion is yellow
The magnetic moment of a transition metal ion is 15BM. 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(NH3)6]3+
  • [Fe(CN)6]3
  • [Fe(CN)6]4
  • [Zn(NH3)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 [Ar]3d5 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?
  • Ni2+
  • Fe3+
  • Ti4+
  • Cu2+
(i) BaCO3aq.suspension+Na2CrO4+AcOHMppt
(ii) BaCO3aq.suspension+Na2CrO4+HCNNppt.
Which is the correct option regarding the given reactions?
  • M and N are the same and characterized as BaCrO4
  • M is BaCrO4 and N stands for no precipitate
  • M is BaCrO4 and N is BaCO3
  • M stands for no precipitate and N is BaCrO4
Identify the oxidation states of titanium (Z=22) and copper (Z=29) in their colourless compounds:
  • Ti3+,Cu2+
  • Ti2+,Cu2+
  • Ti4+,Cu+
  • Ti4+,Cu2+
Which one of the following shows maximum paramagnetic character?
  • [Fe(CN)6]3
  • [Fe(CN)6]4
  • [Cr(H2O)6]3+
  • [Cu(H2O)6]2+
The incorrect statement is :
  • Cu2+ salts give red colour borax bead test in reducing flame.
  • Cu2+ and Ni2+ ions give black colour precipitate with H2S in the presence of HCl solution.
  • Ferric ion gives blood red colour with potassium thiocyanate.
  • Cu2+ 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 TiF26, CoF36, Cu2Cl2 and NiCl24, the colourless sphere are..... 
  • Cu2Cl2, NiCl24
  • TiF26, Cu2Cl2
  • CoF36, NiCl24
  • TiF26, CiF36
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):-
  • KMnO4,K2Cr2O7 charge transfer spectra
  • Halogen HOMO-LUMO transition
  • [Ti(NH3)6]+3 d-d transition
  • CrO2Cl2,CrO24 d-d transition
Mx+ 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(NH3)4]2+ complex is:-
  • 1.732 B.M.
  • 2.2 B.M.
  • 3.87 B.M.
  • 5.96 B.M.
Which of the following pair have almost similar size
  • Ti22 and Zr40
  • Nb41 and Ta73
  • Y39 and La57
  • Ca20 and Ir31
In K2Cr2O7, every Cr is linked to:
  • Two O-atoms
  • Three O-atoms
  • Four O-atoms
  • Five O-atoms
Find the spin magnetic moment of the Fe3+.
  • 5.91
  • 4.89
  • 3.87
  • none of these
CrO24 (yellow) pH=XpH=Y Cr2O27 (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?
  • Co2+
  • Mn3+
  • Cu+
  • Ni2+
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 M2+ has a magnetic moment 35. what is the atomic number of the metal?
  • 24
  • 25
  • 26
  • 27
Orbital angular momentum of e (last filled ) in Cr is 
  • Zero
  • 2h2π
  • 6h2π
  • 12h2π
An iron 25Mnx+ 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 [NiCI4]2 is:
  • 5.46 BM
  • 2.83 BM
  • 1.41 BM
  • 1.82 BM
The metal ion which is not colored is: 
  • Fe3+
  • V2+
  • Zn2+
  • Ti3+
Which of the following lanthanum ions is diamagnetic?
  • Ce4+
  • Sm2+
  • Eu2+
  • Yb2+
Magnetic moment 2.84 B.M is given by:- 
  • Ti3+
  • Cr2+
  • Co2+
  • Ni2+
Colourless ion is:
  • [Fe(CN)6]3
  • [Ti(H2O)6]+3
  • [Sc(H2O)6]+3
  • [Cu(NH3)4]+2
The correct order of spin -only magnetic moments among the following is :
(Atomic number : Mn=25,Co+27,Ni=28,Zn=30)
  • [ZnCl4]2>[NiCl4]2>[CoCl4]2>[MnCl4]2
  • [CoCl4]2>[MnCl4]2>[NiCl4]2>[ZnCl4]2
  • [MnCl4]2>[CoCl4]2>[NiCl4]2>[ZnCl4]2
  • [NiCl4]2>[CoCl4]2>[MnCl4]2>[ZnCl4]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 
  • FeSO4+H2O2
  • Zn+HCl
  • Sn+HCl
  • None of the above
The number of unpaired electron(s) in [Fe(H2O)6]2+ is 
  • 1
  • 2
  • 3
  • 4
Copper sulphate disolves in excess of KCN to give:
  • Cu(CN)2
  • CuCN
  • [Cu(CN)4]3
  • [Cu(CN)4]2
Which of the following ions has maximum magnetic moment?
  • Mn2+
  • Fe2+
  • V3+
  • Ti2+
The d-electronic configuration of Cr2+,Mn2+,Fe2+ and Ni2+ are 3d4,3d5,3d6 and 3d8 respectively. Which one of the following aqua complexes will exhibit the maximum paramagnetic character?
  • [(Fe(H2O))6]2+
  • [(Ni(H2O))6]2+
  • [(Cr(H2O))6]2+
  • [(Mn(H2O))6]2+
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