multiple-choice questions (MCQs). This edition covers transition metal chemistry, including magnetic properties, oxidation states, and complex formation, with mixed-question logic to challenge your conceptual grasp.
B.Sc. II Year Inorganic Chemistry MCQs – Randomized Quiz on Transition Metals
Looking to test your knowledge of transition metals, their oxidation states, magnetic moments, and coordination compounds? This randomized collection of MCQs for B.Sc. Chemistry (2nd Year) students is packed with questions you might encounter in exams—complete with brief explanations for clarity.
Randomized Inorganic Chemistry MCQs with Answers
1. A transition metal ion has a magnetic moment of 5.92 B.M. The number of unpaired electrons is:
- (a) 2
- (b) 3
- (c) 4
- (d) 5 (Correct)
Explanation:
μ = √[n(n+2)] = √[5(5+2)] = √35 ≈ 5.92 → n = 5 unpaired electrons
2. Which statement about copper sulphate is incorrect?
- (a) It reacts with KI to give I₂
- (b) It reacts with KCl to give Cl₂ (Correct)
- (c) It reacts with NaOH and glucose
- (d) It gives CuO on strong heating
Explanation:
KCl doesn't oxidize Cu²⁺; hence Cl₂ is not liberated.
3. Chloroplatinic acid is:
- (a) Monobasic
- (b) Dibasic (Correct)
- (c) Tribasic
- (d) Tetrabasic
Explanation:
Chloroplatinic acid (H₂PtCl₆) is dibasic, releasing two H⁺ ions.
4. TiCl₄ fumes in moist air and hydrolyzes to give:
- (a) Ti
- (b) TiOCl₂
- (c) TiO
- (d) Ti(OH)₄ (Correct)
Explanation:
TiCl₄ hydrolyzes to form Ti(OH)₄, which gives off fumes due to HCl vapor.
5. Which element exhibits the highest oxidation state among the following?
- (a) Sc
- (b) Fe
- (c) Zn
- (d) Mn (Correct)
Explanation:
Manganese exhibits a +7 oxidation state (e.g., in KMnO₄).
6. Which of the following ions is colourless in aqueous solution?
- (a) Ti³⁺
- (b) V³⁺
- (c) Cr³⁺
- (d) Sc³⁺ (Correct)
Explanation:
Sc³⁺ has no unpaired d-electrons (3d⁰), hence no d-d transitions—colourless.
7. Why is cuprous ion (Cu⁺) colourless and cupric ion (Cu²⁺) coloured?
- (a) Cu⁺ has incomplete d-orbital
- (b) Cu²⁺ has full d-orbital
- (c) Both have unpaired electrons
- (d) Cu⁺ has full d-orbital; Cu²⁺ has unpaired electrons (Correct)
Explanation:
Cu⁺ = 3d¹⁰ (no unpaired electrons); Cu²⁺ = 3d⁹, unpaired electrons cause colour.
8. The purple colour of [Ti(H₂O)₆]³⁺ is due to:
- (a) Unpaired d electrons
- (b) Electron transfer (Correct)
- (c) Intermolecular vibration
- (d) Water molecules
Explanation:
Purple colour arises from d-d transitions caused by electronic transfer.
9. Which oxide of manganese is amphoteric?
- (a) MnO
- (b) MnO₂
- (c) Mn₂O₃
- (d) Mn₂O₇ (Correct)
Explanation:
Mn₂O₇ exhibits both acidic and basic character—amphoteric.
10. Acidified chromic acid with H₂O₂ gives blue color due to:
- (a) CrO
- (b) Cr₂O₃
- (c) CrO₅ (Correct)
- (d) H₂Cr₂O₇
Explanation:
The blue colour appears due to CrO₅ (chromium pentoxide).
11. In the dichromate ion (Cr₂O₇²⁻):
- (a) 4 Cr–O bonds are equivalent
- (b) 6 Cr–O bonds are equivalent
- (c) All Cr–O bonds are equivalent
- (d) Cr–O bonds are non-equivalent (Correct)
Explanation:
In dichromate, Cr–O bonds vary, involving bridging and terminal oxygens.
12. Why is high Mn content added to railway steel?
- (a) Provides hardness (Correct)
- (b) Forms oxides
- (c) Removes oxygen and sulfur
- (d) Exhibits high oxidation states
Explanation:
Manganese hardens steel and increases wear resistance—ideal for rail tracks.
13. In the nitroprusside ion, Fe exists as:
- (a) Fe⁺
- (b) Fe²⁺ (Correct)
- (c) Fe³⁺
- (d) Fe⁴⁺
Explanation:
In [Fe(CN)₅NO]²⁻, Fe is in +2 oxidation state.
FAQs on Randomized Transition Metal Chemistry
Q1. How is magnetic moment related to unpaired electrons?
Answer: μ = √[n(n+2)] where n = number of unpaired electrons. Used for identifying electronic configurations.
Q2. Why are some transition metal ions coloured?
Answer: Due to d–d electronic transitions between partially filled d-orbitals.
Q3. What causes fuming of TiCl₄ in moist air?
Answer: Hydrolysis produces HCl vapors, causing fumes.
Q4. Why is Cu⁺ colourless but Cu²⁺ coloured?
Answer: Cu⁺ has a full 3d¹⁰ configuration; Cu²⁺ has unpaired electrons enabling colour via d–d transitions.
Conclusion
Transition metal chemistry is full of fascinating properties—variable oxidation states, magnetism, colour, and catalysis. By solving randomized MCQs like these, you strengthen your exam confidence and reinforce essential concepts. Bookmark this blog for revision and stay tuned for our next post!
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