d- and f-Block Elements · Question 24

Identify the incorrect statement.

1. 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.
2. Interstitial compounds are those that are formed when small atoms like H, C or N are trapped inside the crystal lattices of metals.
3. The oxidation states of chromium in CrO42- and Cr2O72- are not the same.
4. Cr2+ (d4) is a stronger reducing agent than Fe2+ (d6) in water.

The manganate and permanganate ions are tetrahedral due to :

1. The -bonding involves overlap of p-orbitals of oxygen with p-orbitals of manganese
2. The -bonding involves overlap of d-orbitals of oxygen with d-orbitals of manganese
3. The -bonding involves overlap of p-orbitals of oxygen with d-orbitals of manganese
4. There is no -bonding

Which one of the following ions exhibits d-d transition and paramagnetism as well?

1. CrO42-
2. Cr2O72-
3. MnO4-
4. MnO42-

The reason for greater range of oxidation states in actinoids is attributed to

1. actinoid contraction
2. 5f, 6d and 7s levels having comparable energies
3. 4f and 5d levels being close in energies
4. the radioactive nature of actinoids.

Which one of the following statements is correct when SO2 is passed through acidified K2Cr2O7 solution?

1. SO2 is reduced.
2. Green Cr2(SO4)3 is formed.
3. The solution turns blue.
4. The solution is decolourised.

The electronic configuration of Eu (Atomic No. 63), Gd (Atomic No. 64) and Tb (Atomic No. 65) are

1. [Xe]4f6 5d1 6s2, [Xe]4f7 5d1 6s2 and [Xe]4f8 5d1 6s2
2. [Xe]4f7 6s2, [Xe]4f7 5d1 6s2 and [Xe]4f9 6s2
3. [Xe]4f7 6s2, [Xe]4f8 6s2 and [Xe]4f8 5d1 6s2
4. [Xe]4f6 5d1 6s2, [Xe]4f7 5d1 6s2 and [Xe]4f9 6s2

Which one of the following statements related to lanthanoids is incorrect?

1. Europium shows +2 oxidation state.
2. The basicity decreases as the ionic radius decreases from Pr to Lu.
3. All the lanthanons are much more reactive than aluminium.
4. Ce(+4) solutions are widely used as oxidizing agent in volumetric analysis.

Gadolinium belongs to 4f series. Its atomic number is 64. Which of the following is the correct electronic configuration of gadolinium?

1. [Xe]4f9 5s1
2. [Xe]4f7 5d1 6s2
3. [Xe]4f6 5d2 6s2
4. [Xe]4f8 6d2

Magnetic moment 2.84 B.M. is given by (At. nos. Ni = 28, Ti = 22, Cr = 24, Co = 27)

1. Cr2+
2. Co2+
3. Ni2+
4. Ti3+

Because of lanthanoid contraction, which of the following pairs of elements have nearly same atomic radii? (Numbers in the parenthesis are atomic numbers)

1. Zr(40) and Hf(72)
2. Zr(40) and Ta(73)
3. Ti(22) and Zr(40)
4. Zr(40) and Nb(41)