B.Sc. II Year (Inorganic Chemistry), focusing on the first transition series and important elements like Cr, Ni, Pt, and Mn.
B.Sc. II Year Inorganic Chemistry MCQs – First Transition Series, Chromium, Nickel, and Platinum
If you're preparing for B.Sc. Chemistry (2nd Year) exams, mastering the first transition series elements like Chromium (Cr), Nickel (Ni), Platinum (Pt), and Manganese (Mn) is essential. This blog post covers some important multiple-choice questions (MCQs) on the topic, along with detailed explanations to help boost your understanding and exam readiness.
Important MCQs on Transition Elements
1. Chromite is the ore of:
- (a) Cr (Correct)
- (b) Mn
- (c) Ni
- (d) Pt
Explanation: Chromite (FeCr₂O₄) is the principal ore of Chromium.
2. Mond’s Process is used in the purification of:
- (a) Cr
- (b) Ti
- (c) Ni (Correct)
- (d) Pt
Explanation: In the Mond process, Nickel forms a volatile compound, Nickel carbonyl (Ni(CO)₄), which is decomposed to get pure Ni.
3. Dimethyl glyoxime is used for the gravimetric estimation of:
- (a) Fe²⁺
- (b) Cr³⁺
- (c) Ni²⁺ (Correct)
- (d) Pt²⁺
Explanation: Dimethyl glyoxime forms a red precipitate with Ni²⁺ and is used for its estimation.
4. The catalyst used in the hydrogenation of oils is:
- (a) Fe
- (b) Mn
- (c) Ni (Correct)
- (d) Pt
Explanation: Finely divided nickel is commonly used as a catalyst in hydrogenation reactions.
5. Which metal forms a volatile carbonyl used in its extraction?
- (a) Ti
- (b) Ni (Correct)
- (c) Pt
- (d) Cr
Explanation: Nickel forms Ni(CO)₄, a volatile carbonyl compound, exploited in its purification.
6. The highest oxidation state in the first transition series is shown by:
- (a) Cr
- (b) Mn (Correct)
- (c) Co
- (d) Cu
Explanation: Manganese shows oxidation states from +2 to +7, the highest in the first transition series.
7. Which ion is not expected to be coloured?
- (a) Mn²⁺
- (b) Fe
- (c) Ti³⁺
- (d) Cu⁺ (Correct)
Explanation: Cu⁺ has a completely filled d-orbital (3d¹⁰), hence it is colourless.
8. Used as calibrant in magnetic measurements:
- (a) CoCl₂
- (b) KCu(CN)₂
- (c) CoHg(CNS)₄
- (d) Fe₃O₄ (Correct)
Explanation: Fe₃O₄ (magnetite) is used as a standard calibrant due to its strong magnetic properties.
9. Number of unpaired electrons in Fe³⁺ (Z = 26):
- (a) 4
- (b) 5 (Correct)
- (c) 6
- (d) 2
Explanation: Fe³⁺ = [Ar]3d⁵; has 5 unpaired electrons.
10. Divalent compound with max magnetic moment in the first series:
- (a) Mn (Correct)
- (b) Fe
- (c) Cu
- (d) Cr
Explanation: Mn²⁺ has 5 unpaired electrons, leading to the highest magnetic moment.
11. Which does not belong to the first transition series?
- (a) Silver (Correct)
- (b) Cobalt
- (c) Chromium
- (d) Vanadium
Explanation: Silver (Ag) is part of the second transition series, not the first.
12. d-block elements show all except:
- (a) Variable oxidation states
- (b) Catalytic properties
- (c) Natural radioactivity (Correct)
- (d) Colour of compounds
Explanation: Natural radioactivity is not a common feature of d-block elements.
13. Expected magnetic moment of Ti³⁺:
- (a) 4.90
- (b) 2.84
- (c) 1.73 (Correct)
- (d) 0
Explanation: Ti³⁺ has 1 unpaired electron. Magnetic moment = √[n(n+2)] = √3 = 1.73 B.M.
14. Highest magnetic moment among the following:
- (a) Co²⁺
- (b) Cu²⁺
- (c) Ni
- (d) Mn²⁺ (Correct)
Explanation: Mn²⁺ has 5 unpaired electrons, giving it the highest magnetic moment.
15. Which is expected to be diamagnetic?
- (a) CrCl
- (b) CuCl (Correct)
- (c) ZnCl₂
- (d) CuSO₄
Explanation: Cu⁺ in CuCl has a full d⁰ orbital, making it diamagnetic.
16. The first transition series comprises elements from:
- (a) Scandium to Zinc (Correct)
- (b) Lanthanum to Hafnium
- (c) Chromium to Copper
- (d) Titanium to Nickel
Explanation: The first transition series ranges from Sc (Z=21) to Zn (Z=30).
FAQs
Q1. What is the most common oxidation state shown by transition metals?
Answer: +2 is the most common oxidation state among first-row transition metals.
Q2. Why are transition metals colored?
Answer: Due to d-d electronic transitions within partially filled d-orbitals.
Q3. Which element shows the highest oxidation state in the first transition series?
Answer: Manganese (+7 oxidation state in KMnO₄).
Q4. What makes a metal suitable for catalysis?
Answer: Their ability to adopt multiple oxidation states and form complexes with reactants.
Conclusion
Understanding the properties and chemical behavior of transition elements like Cr, Ni, Mn, and Pt is key to excelling in B.Sc. II Year Inorganic Chemistry. Use these MCQs as a quick revision guide to strengthen your preparation. Keep practicing, and stay tuned for more topic-wise MCQ blogs!
إرسال تعليق