CBSE Class 12 Chemistry The d and f Block Elements MCQs Set C

Question. Malachite is an ore of:
(a) Silver
(b) Mercury
(c) Magnesium
(d) Copper

Answer : D

Question. The chief ore of Hg is:
(a) Pyrolusite
(b) Bauxite
(c) Galena
(d) Cinnabar

Answer : D

Question. The transition element which shows the highest oxidation state is:
(a) Iron
(b) Vanadium
(c) Manganese
(d) Chromium

Answer : C

Question. Gun metal is:
(a) Cu + Zn
(b) Cu + Sn + Zn
(c) Cu + Sn
(d) Zn + Sn

Answer : B

Question. Transition elements form coloured ions due to :
(a) d-d transition
(b) fully filled d-orbitals
(c) smaller atomic radii
(d) availability of s-electrons

Answer : A

Question. CuSO₄ and KCN react to produce : 
(a) CuCN₂
(b) CuCN
(c) K₃[Cu(CN)₄]
(d) K₄[Cu(CN)₆ ]

Answer : C

Question. Which of the following is greatest paramagnetic?
(a) Cu⁺
(b) Fe²⁺
(c) Fe³⁺
(d) Cu²⁺

Answer : C

Question. The Mohr’s salt is shown by:
(a) FeSO₄ (NH₄)₂SO₄.6H₂O
(b) FeSO₄ (NH₃)2SO4.6H₂O
(c) K2SO₄Al₂ (SO₄ )3.24H₂O
(d) FeSO₃(NH₂ )4SO₄.6H₂O

Answer : A

Question. German silver is an alloy of:
(a) Fe, Cr, Ni
(b) Ag, Cu Au
(c) Cu, Zn, Ni
(d) Cu, Zn, Sn

Answer : C

Question. The electronic configuration of Cu is
(a) [Ne] 3s² ,3p⁶ ,3d⁹ ,4s²
(b) [Ne] 3s² , 3p⁶ ,3d¹⁰ ,4s¹
(c) [Ne] 3s² ,3p⁶ ,3d³ ,4s² ,4p⁶
(d) [Ne] 3s² ,3p⁵ ,3d⁵ ,4s² ,4p⁴

Answer : B

Question. Metal ion responsible for the Minamata disease is
(a) Co²⁺
(b) Hg²⁺ 
(c) Cu²⁺
(d) Zn²⁺

Answer : B

Question. Cupric compounds are more stable than their cuprous counterparts in solid state. This is because
(a) the endothermic character of the 2nd IP of Cu is not so high
(b) size of Cu²⁺ is less than Cu⁺
(c) Cu²⁺ has stable electronic configurations compared to cu⁺
(d) the lattice energy released for cupric compounds is must higher than Cu⁺

Answer : D

Question. Which is not true for describing the catalytic activity of transition metals?
(a) Their ability to adopt multiple oxidation states
(b) Their ability to form bonds between reactant molecule and atoms of the surface of catalysts
(c) Increasing the concentration of reactants at the catalyst surface
(d) Strengthening the bonds in the reacting molecules

Answer : D

Question. Which one of the following transition element has the lowest value of enthalpy of atomisation?
(a) Cr
(b) Cu
(c) Zn
(d) M

Answer : C

Question. Which one of the following ions has same number of unpaired electrons as those present in V³⁺ ion? 
(a) Fe³⁺
(b) Ni²⁺
(c) Mn²⁺
(d) Cr³⁺

Answer : B

Question. What is the ground state electron configuration of the Mn²⁺ ion?
(a) [Ar]4s¹,3d⁵
(b) [Ar]4s²,3d³
(c) [Ar]3d⁵
(d) [Ar]3d⁴

Answer : C

Question. The colour of transition metal compound is due to
(a) complete ns subshell
(b) small size metal ions
(c) incomplete (n – 1)d-subshell
(d) absorption of light in UV region

Answer : C

Question. Paramagnetism is exhibited due to which one of the following reason?
(a) Presence of unpaired electrons
(b) Presence of completely filled electronic subshell
(c) By non-transition element
(d) By elements with noble gas configuration

Answer : A

Question. Which of the following radioisotopes is used as anticancerous?
(a) Na-24
(b) C-14
(c) U-235
(d) Co-60

Answer : D

Question. The composition of duralumin is :
(a) Al 94%, Mg 6%
(b) Cu 56%, Zn 24%, Ni 20%
(c) Cu 95%, Al 5%
(d) Al 95%, Cu 4%, Mn 0.5%, Mg 0.5%

Answer : D

Question. White silver surface turns black when O3 is passed over it. This is due to the formation of
(a) silver hydroxide
(b) freshly reduced silver which is black in colour
(c) silver oxide
(d) a complex compound of silver and ozone

Answer : B

Question. In which of the following cases, the stability of two oxidation states is correctly represented
(a) Ti³⁺ > Ti⁴⁺
(b) Mn²⁺ > Mn³⁺
(c) Fe²⁺ > Fe³⁺
(d) Cu⁺ > Cu²⁺

Answer : B

Question. Cuprous ion is colourless while cupric ion is coloured because
(a) Both have half filled p-and d-orbitals
(b) Cuprous ion has incomplete d-orbitaland cupric ion has a complete d-orbital
(c) Both have unpaired electrons in the d-orbitals
(d) Cuprous ion has complete d-orbital and cupric ion has an incomplete d-orbital.

Answer : D

Question. A compound of a metal ion Mx+ (Z = 24) has a spin only magnetic moment of 15 Bohr Magnetons. The number of unpaired electrons in the compound are
(a) 2
(b) 4
(c) 5
(d) 3

Answer : D

Question. Identify the incorrect statement among the following :
(a) Lanthanoid contraction is the accumulation of successive shrinkages.
(b) As a result of lanthanoid contraction, the properties of 4d series of the transition elements have no similarities with the 5d series of elements.
(c) Shielding power of 4f electrons is quite weak.
(d) There is a decrease in the radii of the atoms or ions as one proceeds from La to Lu.

Answer : B

Question. Consider the following statements 
(I) La(OH)₃ is the least basic among hydroxides of lanthanides.
(II) Zr⁴⁺ and Hf⁴⁺ posses almost the same ionic radii.
(III) Ce⁴⁺ can as an oxidizing agent.
Which of the above is/are true ?
(a) (I) and (III)
(b) (II) and (III)
(c) (II) only
(d) (I) and (II)

Answer : B

Question. For d-block elements the first ionization potential is of the order
(a) Zn > Fe > Cu > Cr
(b) Sc = Ti < V = Cr
(c) Zn < Cu < Ni < Co
(d) V > Cr > Mn > Fe

Answer : A

Question. Sc (Z = 21) is a transition element but Zn (Z = 30) is not because
(a) both Sc³⁺ and Zn²⁺ ions are colourless and form white compounds
(b) in case of Sc, 3d orbitals are partially filled but in Zn these are filled
(c) last electron is assumed to be added to 4s level in case of Zn
(d) both Sc and Zn do not exhibit variable oxidation states

Answer : B

Question. Which of the following ions has electronic configuration [Ar]3d6?
(a) Ni³⁺
(b) Mn³⁺
(c) Fe³⁺
(d) Co³⁺

Answer : D

Question. The number of water molecules in Mohr’s salt is :
(a) 2
(b) 4
(c) 6
(d) 8

Answer : C

Question. Philosopher’s wool on heating with BaO at 1100°C produces :
(a) Ba + ZnCl₂
(b) BaCdO₂
(c) BaZnO₂
(d) BaO₂ + Zn

Answer : C

Question. Which of the following is not an ore of iron?
(a) limonite
(b) casiterite
(c) magnetite
(d) none of these

Answer : B

Question. The colourless species is :
(a) VCl₃
(b) VOSO₄
(c) Na₃VO₄
(d) [V(H₂O)₆]SO₄. H₂O

Answer : C

Question. Lanthanide for which +II and +III oxidation states are common is :
(a) La
(b) Pr
(c) Ce
(d) Eu

Answer : D

Question. Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other, in :
(a) Ti⁺, Ti³⁺
(b) Cu⁺ , Cu²⁺
(c) Cr²⁺, Cr³⁺
(d) V^2+, VO²⁺

Answer : A

Question. F₂ is formed by reacting K₂MnF₆ with : 
(a) SbF₅
(b) MnF₃
(c) KSbF₆
(d) MnF₄

Answer : A

Question. The colour imparted by Co(Il) compounds to glass is:
(a) Green
(b) Deep blue
(c) Yellow
(d) Red

Answer : B

Question. M₁ , Q and R, respectively are
(a) Zn^2- , KCN and HCl
(b) Ni²⁺ , HCI and KCN
(c) Cd²⁺ , KCN and HCl
(d) Co²⁺, HCI and KCN

Answer : B

Question. Reagent S is
(a) K₄ [Fe(CN)₆ ]
(c) K₂CrO₄
(b) Na₂HPO₄
(d) KOH

Answer : D

Question. Mercury is a liquid metal because
(a) it has a completely filled d-orbital that causes d-d overlapping
(b) it has completely filled d-orbital that prevents d-d overlapping
(c) it has a completely filleds-orbital
(d) it has a small atomic size

Answer : B

Question. Which of the following has the maximum unpaired d-electrons?
(a) Fe²⁺
(b) Cu⁺
(c) Zn
(d) Ni³⁺

Answer : A

Question. The element which forms ions in dimeric state is
(a) mercury
(b) nickel
(c) iron
(d) cadmium

Answer : A

Question. Which one of these is not known?
(a) CuCl₂
(b) Cul₂
(c) CuF₂
(d) CuBr₂

Answer : B

Question. Which of the following compound is coloured?
(a) TiCl₃
(b) FeCl₃ 
(c) CoCl₂
(d) All of these

Answer : D

Question. The purple colour of KMnO₄ is due to the transition 
(a) C.T. (L → M)
(b) C.T. (M → L)
(c) d – d
(d) p – d

Answer : A

Question. To obtain silver from silver amalgam, it is heated in vessel which is made of –
(a) Cu
(b) Fe
(c) Ni
(d) Zn

Answer : B

Question. The compounds containing complex oxyanion CrO4^2- are intensely yellow coloured because
(a) Chromium ion in CrO4² is a transition metal ion 
(b) Cr and O are Π-bonded and the allowed Π → Π* transition occurs in the visible region
(c) Cr → O charge transfer is responsible for yellow colour
(d) Compounds have strong absorption at ~ 640 nm

Answer : C

Question. The only cations present in a slightly acidic solutions are Fe3+, Zn²⁺ and Cu²⁺. The reagent that when added in excess to this solution would identify and separate Fe³⁺ in one step is
(a) 2 M HCI
(b) 6 M NH₃ 
(c) 6 M NaOH
(d) H₂S gas

Answer : B

Question. The colour of copper sulphide is
(a) Blue
(b) Black
(c) Red
(d) Green

Answer : B

Question. Which one of the following statements concerning lanthanide elements is false?
(a) Lanthanides are separated from one another by ion exchange method
(b) The ionic radii of trivalent lanthanides steadily increase with increase in atomic number
(c) All lanthanides are highly dense metals
(d) Most characteristic oxidation state of lanthanides is +3

Answer : B

Question. Among the following series of transition metal ions, the one where all metal ions have 3d2 electronic configuration is
[At. nos. Ti = 22, V = 23, Cr = 24, Mn = 25]
(a) Ti³⁺, V²⁺, Cr³⁺, Mn⁴⁺
(b) Ti⁺, V⁴⁺, Cr⁶⁺, Mn⁷⁺
(c) Ti⁴⁺, V³⁺, Cr²⁺, Mn³⁺
(d) Ti²⁺, V³⁺, Cr⁴⁺, Mn⁵⁺ 

Answer : D

Question. Which of the following has more unpaird d-electrons?
(a) N³⁺
(b) Fe²⁺
(c) Zn⁺
(d) Cu⁺

Answer : B