Q.1. Zr (Z=40) and Hf (Z=72) have similar atomic and ionic radii because of: (2021)
(a) lanthanoid contraction
(b) having similar chemical properties
(c) belonging to same group
(d) diagonal relationship
Due to lanthanoid contraction, Zr and Hf has similar atomic and ionic radii.
Q.2. The incorrect statement among the following is : (2021)
(a) Lanthanoids are good conductors of heat and electricity.
(b) Actinoids are highly reactive metals, especially when finely divided.
(c) Actinoid contraction is greater for element to element than Lanthanoid contraction.
(d) Most of the trivalent Lanthanoid ions are colorless in the solid state.
Most of the trivalent lanthanoid ions are coloured in the solid state.
Q.3. Match List-I with List-II (2021)
Choose the correct answer from the options given below
(a) (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)
(b) (a)-(iv), (b)-(i), (c)-(ii), (d)-(iii)
(c) (a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)
(d) (a)-(ii), (b)-(iv), (c)-(iii), (d)-(i)
Q.4. Identify the incorrect statement. (2020)
A: Interstitial compounds are those that are formed when small atoms like H, C or N are trapped inside the crystal lattices of metals.
B: The oxidation states of chromium in CrO24- and Cr2O72- are not the same.
C: Cr2+(d4) is a stronger reducing agent than Fe2+(d6) in water.
D: The transition metals and their compounds are known for their catalytic activity due to their ability to adopt multiple oxidation states and to form complexes.
A. Interstitial compounds are those compounds that are formed when small atoms like H, B, C or N are trapped inside crystal lattices of metals.
B. Oxidation state of chromium in CrO42– & Cr2O72– are +6 (same)
C. Fact Cr2+ is stronger reducing agent than Fe2+ in water on the basis of standard reduction potential.
D. Transition metals are one of the best available catalyst due to their ability to adopt multiple oxidation states & to form complexes.
Q.5. The manganate and permanganate ions are tetrahedral, due to : (2019)
A: The π -bonding involves overlap of p-orbitals of oxygen with d-orbitals of manganese
B: There is no π-bonding
C: The π -bonding involves overlap of p-orbitals of oxygen with p-orbitals of manganese
D: The π -bonding involves overlap of d-orbitals of oxygen with d-orbitals of manganese
Manganate (MnO42-) :
⇒ π-bonds are of dπ-pπ type
Permanganate (MnO4-) :
⇒ π-bonds are of dπ-pπ type
Q.6. Name the gas that can readily decolourise acidified KMnO4 solution : (2017)
Q.7. HgCl2 and I2 both when dissolved in water containing I– ions the pair of species formed is : (2017)
A: HgI2, I–
C: Hg2I2, I–
D: HgI2, I¯3
Q.8. The reason for greater range of oxidation states in actinoids is attributed to :- (2017)
A: actinoid contraction
B: 5f, 6d and 7s levels having comparable energies
C: 4f and 5d levels being close in energies
D: the radioactive nature of actinoids
Minimum energy gap between
5f, 6d & 7s subshell. Thats why e– excitation will be easier.
Q.9. Which one of the following statements is correct when SO2 is passed through acidified K2Cr2O7 solution? (2016)
A: Green Cr2(SO4)3 is formed.
B: The solution turns blue
C: The solution is decolourized.
D: SO2 is reduced.
K2Cr2O7 → Cr2(SO4)3 green solution obtain where as SO2 oxidise into sulphate SO42-
(K2Cr2O7 + SO2 + H2SO4 → Cr2(SO4)3 + H2O + K2SO4)
Q.10. The electronic configurations of Eu (Atomic No. 63) Gd (Atomic No. 64) and Tb (Atomic No. 65) are : (2016)
A: [Xe]4f7 6s2, [Xe]4f75d16s2 and [Xe]4f96s2
B: [Xe]4f7 6s2, [Xe]4f8 6s2 and [Xe]4f8 5d16s2
C: [Xe]4f6 5d16s2, [Xe]4f7 5d16s2 and [Xe]4f9 5d16s2
D: [Xe]4f6 5d16s2, [Xe]4f7 5d16s2 and [Xe]4f8 5d16s2
63Eu → [Xe] 4f7 6s2
64Gd → [Xe] 4f7 5d16s2
65Tb → [Xe] 4f9 5d06s2
Q.11. Which of the following processes does not involve oxidation of iron ? (2015)
A: Liberation of H2 from steam by iron at high temperature
B: Rusting of iron sheets
C: Decolourization of blue CuSO4 solution by iron
D: Formation of Fe(CO)5 from Fe
Q.12. Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic radii ? (Numbers in the parenthesis are atomic numbers). (2015)
A: Zr (40) and Ta (73)
B: Ti (22) and Zr (40)
C: Zr (40) and Nb (41)
D: Zr (40) and Hf (72)
Q.13. Reason of lanthanoid contraction is : (2014)
A: Decreasing nuclear charge
B: Decreasing screening effect
C: Negligible screening effect of 'f ' orbitals
D: Increasing nuclear charge
Q.14. The reaction of aqueous KMnO4 with H2O2 in acidic conditions gives : (2014)
A: Mn2+ and O3
B: Mn4+ and MnO2
C: Mn4+ and O2
D: Mn2+ and O2
(2KMnO4 + 3H2SO4 + 5H2O2 → K2SO4 + 2MnSO4 + 8H2O + 5O2)