The d- and f-Block Elements Chapter-Wise Test 2

Correct answer Carries: 4.

Wrong Answer Carries: -1.

What is the magnetic moment (in BM) of a transition metal ion with 4 unpaired electrons?

Using the spin-only formula: μ = √[n(n+2)] = √[4(4+2)] = √24 ≈ 4.90 BM

3.87
4.90
5.92
2.83
2

Which catalyst is used in the Contact Process for sulfuric acid production?

V2O5 (Vanadium pentoxide) catalyzes the oxidation of SO2 to SO3.

Fe
V2O5
Pt
Ni
2

What is the primary reason for the catalytic properties of transition metals?

Variable oxidation states allow transition metals to form unstable intermediate complexes.

High melting points
Variable oxidation states
Large atomic size
Presence of f-electrons
2

Which of the following is NOT a property of transition metal alloys?

Transition metal alloys typically have high melting points, not low melting points.

High hardness
High melting points
Low melting points
Corrosion resistance
3

What is the main reason for the formation of colored ions in transition elements?

d-d transitions of unpaired electrons in incomplete d-orbitals absorb visible light.

Large atomic size
High ionization energy
d-d transitions
Presence of f-electrons
3

Which of the following ions has the electronic configuration [Ar] 3d6?

Fe2+ (Z=26) loses two 4s electrons, resulting in [Ar] 3d6.

Fe3+
Fe2+
Co2+
Ni2+
2

Which of the following transition metal ions is colorless in aqueous solution?

Sc3+ has 3d0 configuration with no d-d transitions possible.

Fe3+
Cu2+
Sc3+
Ni2+
3

What is the magnetic moment (in BM) of Fe3+ ion? (Atomic number of Fe = 26)

Fe3+ has 5 unpaired electrons (3d5). Magnetic moment = √[5(5+2)] = 5.92 BM.

1.73
2.83
5.92
3.87
3

Which actinoid exhibits the +3 oxidation state exclusively?

Actinium (Ac) shows only the +3 oxidation state, similar to lanthanum.

Uranium (U)
Plutonium (Pu)
Actinium (Ac)
Thorium (Th)
3

Which of the following is NOT a use of potassium permanganate?

KMnO4 is an oxidizing agent, not used as a reducing agent.

Disinfectant
Oxidizing agent in organic chemistry
Reducing agent in metallurgy
Bleaching agent
4

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