CUET UG Chemistry Booster Test - 2 Bonding and Applications
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QUESTION 1 OF 20
What theoretical approach is primarily used in the Valence Bond Theory to yield a set of equivalent orbitals of definite geometry?
QUESTION 2 OF 20
Consider the following regarding the limitations of early bonding models. Choose the correct statements:
1. Werner's theory successfully explained the exact geometries of molecules.
2. Werner's theory failed to explain why coordination compounds have characteristic magnetic properties.
3. VBT and CFT were introduced to answer why bonds in these compounds have directional properties.
4. Werner's secondary valency completely predicted the colour of compounds.
QUESTION 3 OF 20
What is the IUPAC name of the complex [CoF₆]³⁻ which utilizes sp³d² hybridisation?
QUESTION 4 OF 20
Which of the following is true for the outer orbital complex [CoF₆]³⁻?
QUESTION 5 OF 20
Match List-I (Octahedral Complex) with List-II (Hybridisation & Magnetic Nature):
| List I | List II |
|---|---|
| 1. [Co(NH₃)₆]³⁺ | a. sp³d², paramagnetic (4 unpaired e⁻) |
| 2. [CoF₆]³⁻ | b. d²sp³, paramagnetic (2 unpaired e⁻) |
| 3. [Mn(CN)₆]³⁻ | c. d²sp³, diamagnetic |
| 4. [FeF₆]³⁻ | d. sp³d², paramagnetic (5 unpaired e⁻) |
QUESTION 6 OF 20
Why is [Ni(CO)₄] diamagnetic despite having tetrahedral geometry?
QUESTION 7 OF 20
Which of the following conditions under Valence Bond Theory guarantees a complex to be diamagnetic?
QUESTION 8 OF 20
The value of the spin-only magnetic moment for [MnBr₄]²⁻ is given as 5.9. The unit for this measurement is:
QUESTION 9 OF 20
CFT is often considered superior to VBT in certain aspects because VBT:
QUESTION 10 OF 20
Which limitation of VBT directly prevents it from predicting whether a 4-coordinate complex will form a particular geometry?
QUESTION 11 OF 20
How does CFT view the fundamental nature of the metal-ligand bond?
QUESTION 12 OF 20
According to the passage, how are neutral molecules treated in CFT?
QUESTION 13 OF 20
In an octahedral complex, the energy of the eg set of orbitals increases by what fraction of Δo relative to the barycentre?
QUESTION 14 OF 20
Why are low spin configurations rarely observed in tetrahedral complexes?
QUESTION 15 OF 20
Arrange the following ligands in decreasing order of crystal field strength:
1. CO
2. NH₃
3. H₂O
4. Cl⁻
QUESTION 16 OF 20
For a d⁴ coordination entity, if Δo > P, what will be the resulting electronic configuration?
QUESTION 17 OF 20
What happens when water is completely removed from [Ti(H₂O)₆]Cl₃ on heating?
QUESTION 18 OF 20
The yellow-red and blue absorption bands in emerald result in the transmission of which colour?
QUESTION 19 OF 20
Identify the reaction type associated with the hypo solution in black and white photography:
QUESTION 20 OF 20
Which chelating ligand is utilized in the medicinal treatment of lead poisoning?
Test Complete!
Answer Review
1 What theoretical approach is primarily used in the Valence Bond Theory to yield a set of equivalent orbitals of definite geometry?
�� VBT uses hybridisation. �� Equivalent orbitals are produced. �� Geometry is determined by hybridisation type.
- Valence Bond Theory explains the geometry of coordination compounds through hybridisation of atomic orbitals. → The metal ion combines suitable orbitals to form equivalent hybrid orbitals directed in space. → These hybrid orbitals accept lone pairs from ligands. → Therefore, Option B is correct.
- �� Option A → Degeneracy splitting is a concept of Crystal Field Theory.
- �� Option C → Spectrochemical pairing is not a VBT principle.
- �� Option D → Dipole interaction is associated with Crystal Field Theory.
Used
- Concept Recall
Application:
- �� Recall the central concept used by VBT to explain geometry.
Final Logic:
- �� VBT explains geometry through hybridisation.
- VBT = Hybridisation
2 Consider the following regarding the limitations of early bonding models. Choose the correct statements:
1. Werner's theory successfully explained the exact geometries of molecules.
2. Werner's theory failed to explain why coordination compounds have characteristic magnetic properties.
3. VBT and CFT were introduced to answer why bonds in these compounds have directional properties.
4. Werner's secondary valency completely predicted the colour of compounds.
�� Werner's theory explained composition. �� Magnetic properties remained unexplained. �� VBT and CFT explained bonding and geometry.
- Statement 1 is incorrect because Werner's theory did not explain exact orbital geometries. → Statement 2 is correct because magnetic behavior could not be explained by Werner's theory. → Statement 3 is correct because VBT and CFT were developed to explain bonding directionality and structure. → Statement 4 is incorrect because Werner's theory could not explain colour. → Therefore, statements 2 and 3 are correct.
- �� Option A → Statement 4 is incorrect.
- �� Option C → Statement 4 is incorrect.
- �� Option D → Statement 1 is incorrect.
Used
- Elimination
Application:
- �� Identify known limitations of Werner's theory.
Final Logic:
- �� Only statements 2 and 3 are correct.
- Werner: Structure Yes, Colour & Magnetism No
3 What is the IUPAC name of the complex [CoF₆]³⁻ which utilizes sp³d² hybridisation?
�� F⁻ is fluorido ligand. �� Complex is anionic. �� Co oxidation state is +3.
- Let oxidation state of Co = x. → x + 6(−1) = −3 → x = +3 → Since the complex ion is negatively charged, the metal name becomes cobaltate. → Therefore, the correct IUPAC name is Hexafluoridocobaltate(III) ion.
- �� Option A → Anionic complexes use "cobaltate."
- �� Option C → Incorrect oxidation state.
- �� Option D → Incorrect oxidation state.
Used
- Substitution
Application:
- �� Calculate oxidation state and apply IUPAC rules.
Final Logic:
- �� Co = +3 and anionic complex → cobaltate(III).
- Anion = Cobaltate
4 Which of the following is true for the outer orbital complex [CoF₆]³⁻?
�� F⁻ is a weak-field ligand. �� Electron pairing does not occur. �� Outer orbital complex is formed.
- Co³⁺ is a d⁶ ion. → F⁻ is a weak-field ligand and cannot force electron pairing. → Hybridisation therefore uses outer 4d orbitals giving sp³d² hybridisation. → Unpaired electrons remain, making the complex paramagnetic. → Hence, Option B is correct.
- �� Option A → F⁻ is not a strong-field ligand.
- �� Option C → d²sp³ corresponds to an inner orbital complex.
- �� Option D → VBT involves orbital overlap.
Used
- Concept Recall
Application:
- �� Determine ligand strength and resulting hybridisation.
Final Logic:
- �� Weak-field ligand → sp³d² → paramagnetic.
- Weak Field = Outer Orbital
5 Match List-I (Octahedral Complex) with List-II (Hybridisation & Magnetic Nature):
| List I | List II |
|---|---|
| 1. [Co(NH₃)₆]³⁺ | a. sp³d², paramagnetic (4 unpaired e⁻) |
| 2. [CoF₆]³⁻ | b. d²sp³, paramagnetic (2 unpaired e⁻) |
| 3. [Mn(CN)₆]³⁻ | c. d²sp³, diamagnetic |
| 4. [FeF₆]³⁻ | d. sp³d², paramagnetic (5 unpaired e⁻) |
�� NH₃ gives diamagnetic Co³⁺ complex. �� F⁻ forms outer orbital complexes. �� CN⁻ is a strong-field ligand.
- 1-c: [Co(NH₃)₆]³⁺ → d²sp³, diamagnetic. → 2-a: [CoF₆]³⁻ → sp³d², paramagnetic (4 unpaired electrons). → 3-b: [Mn(CN)₆]³⁻ → d²sp³, paramagnetic (2 unpaired electrons). → 4-d: [FeF₆]³⁻ → sp³d², paramagnetic (5 unpaired electrons). → Therefore, Option A is correct.
- �� Option B → Incorrect assignment for [Mn(CN)₆]³⁻.
- �� Option C → Incorrect assignment for [Co(NH₃)₆]³⁺.
- �� Option D → Multiple mismatches.
Used
- Option Grouping
Application:
- �� Match ligand strength, hybridisation and magnetic behavior.
Final Logic:
- �� Only Option A contains all correct matches.
- NH₃ Pairing, F⁻ Outer, CN⁻ Strong
6 Why is [Ni(CO)₄] diamagnetic despite having tetrahedral geometry?
�� CO is a strong-field ligand. �� Ni is in zero oxidation state. �� Electron pairing makes the complex diamagnetic.
- In Ni(CO)₄, nickel is in the 0 oxidation state. → Strong-field CO ligands cause pairing of electrons. → All electrons become paired before sp³ hybridisation occurs. → Therefore the complex is diamagnetic despite being tetrahedral.
- �� Option A → Nickel is not in +2 oxidation state.
- �� Option C → Tetrahedral complexes use sp³ hybridisation.
- �� Option D → CO is a strong-field ligand.
Used
- Concept Recall
Application:
- �� Recall the electronic configuration of Ni(CO)₄.
Final Logic:
- �� Strong-field CO causes electron pairing.
- CO Pairs, Ni(CO)₄ No Unpaired
7 Which of the following conditions under Valence Bond Theory guarantees a complex to be diamagnetic?
�� Diamagnetism requires paired electrons. �� No unpaired electrons should remain. �� Hybridisation type alone is insufficient.
- Diamagnetic substances contain no unpaired electrons. → Under VBT, a complex is diamagnetic only when all d electrons become paired. → Therefore, Option B is correct.
- �� Option A → Strong ligands often cause pairing but not always.
- �� Option C → Outer orbital complexes may still be paramagnetic.
- �� Option D → Coordination number alone does not determine magnetism.
Used
- Concept Recall
Application:
- �� Apply the definition of diamagnetism.
Final Logic:
- �� No unpaired electrons = diamagnetic.
- No Unpaired = Diamagnetic
8 The value of the spin-only magnetic moment for [MnBr₄]²⁻ is given as 5.9. The unit for this measurement is:
�� Magnetic moment is expressed in BM. �� BM relates to electron spin. �� Widely used in coordination chemistry.
- The magnetic moment of coordination compounds is commonly expressed in Bohr Magnetons (BM). → The spin-only formula is: μ = √n(n + 2) BM → Therefore, Option C is correct.
- �� Option A → Unit of electric field strength.
- �� Option B → Unit of dipole moment.
- �� Option D → Unit related to conductivity.
Used
- Dimensional/Unit Analysis
Application:
- �� Match the physical quantity with its standard unit.
Final Logic:
- �� Magnetic moment is measured in BM.
- Magnetism = BM
9 CFT is often considered superior to VBT in certain aspects because VBT:
�� VBT cannot explain ligand strength differences. �� CFT introduces crystal field splitting. �� Strong and weak ligands are differentiated.
- One major limitation of VBT is that it does not provide a satisfactory basis for distinguishing strong-field and weak-field ligands. → Crystal Field Theory explains this through differences in crystal field splitting energy. → Hence, Option B is correct.
- �� Option A → Describes CFT, not VBT.
- �� Option C → VBT does not accurately explain kinetic stability.
- �� Option D → Point-charge treatment belongs to CFT.
Used
- Concept Recall
Application:
- �� Compare the explanatory power of VBT and CFT.
Final Logic:
- �� VBT cannot satisfactorily explain ligand strength.
- VBT Can't Rank Ligands
10 Which limitation of VBT directly prevents it from predicting whether a 4-coordinate complex will form a particular geometry?
�� VBT often requires experimental evidence. �� Geometry prediction is not always definitive. �� Four-coordinate complexes are a classic example.
- VBT cannot independently predict whether a four-coordinate complex will be tetrahedral or square planar. → Experimental magnetic measurements are often needed. → This is one of the recognized limitations of the theory. → Therefore, Option A is correct.
- �� Option B → Point-charge assumption belongs to CFT.
- �� Option C → Primary valency is explained by Werner's theory.
- �� Option D → VBT applies to many electronic configurations.
Used
- Concept Recall
Application:
- �� Recall the standard limitations of VBT.
Final Logic:
- �� VBT cannot reliably predict tetrahedral vs square planar geometry.
- 4-Coordinate? VBT Needs Help
11
How does CFT view the fundamental nature of the metal-ligand bond?
�� CFT is an electrostatic model. �� Metal-ligand attraction is ionic. �� Covalent overlap is ignored.
- According to Crystal Field Theory, the metal-ligand bond is considered purely electrostatic. → The positively charged metal ion attracts negatively charged ligands or the negative end of neutral ligand dipoles. → CFT does not involve orbital overlap or covalent bonding concepts. → Therefore, Option B is correct.
- �� Option A → Covalent bonding is not assumed in CFT.
- �� Option C → Synergic bonding is explained through Molecular Orbital Theory.
- �� Option D → Hybridisation is a concept of Valence Bond Theory.
Used
- Contextual/Tonal Matching
Application:
- �� Use the exact statement provided in the passage.
Final Logic:
- �� CFT treats bonding as purely electrostatic.
- CFT = Charges Attract
12
According to the passage, how are neutral molecules treated in CFT?
�� Neutral ligands possess dipole moments. �� CFT treats them as dipoles. �� Examples include NH₃ and H₂O.
- The passage clearly states that neutral molecules are treated as point dipoles in Crystal Field Theory. → Their dipole interaction with the central metal ion causes d-orbital splitting. → Therefore, Option B is correct.
- �� Option A → Anionic ligands are treated as point charges.
- �� Option C → d orbitals are degenerate, not neutral ligands.
- �� Option D → Neutral molecules actively interact with the metal ion.
Used
- Contextual/Tonal Matching
Application:
- �� Extract the exact information from the passage.
Final Logic:
- �� Neutral ligands are treated as point dipoles.
- Neutral Ligand = Dipole
13 In an octahedral complex, the energy of the eg set of orbitals increases by what fraction of Δo relative to the barycentre?
�� eg orbitals point directly toward ligands. �� They experience greater repulsion. �� Their energy increases by +0.6Δo.
- In an octahedral crystal field, the five d orbitals split into t₂g and eg sets. → The eg orbitals (dx²−y² and dz²) experience maximum repulsion. → Their energy rises by: +3/5 Δo = +0.6Δo → Therefore, Option B is correct.
- �� Option A → Represents the lowering of t₂g orbitals (−2/5Δo).
- �� Option C → Relation between Δt and Δo.
- �� Option D → Not the accepted value.
Used
- Formula Recall
Application:
- �� Recall standard octahedral splitting values.
Final Logic:
- �� eg orbitals increase by +3/5 Δo.
- eg Goes Up by 0.6
14 Why are low spin configurations rarely observed in tetrahedral complexes?
�� Tetrahedral splitting is small. �� Pairing energy is usually larger. �� High-spin configurations are favored.
- The tetrahedral crystal field splitting energy (Δt) is only 4/9 of the corresponding octahedral splitting. → Because Δt is usually smaller than the pairing energy (P), electrons prefer to remain unpaired. → Consequently, tetrahedral complexes are generally high spin. → Therefore, Option B is correct.
- �� Option A → Tetrahedral splitting is relatively small.
- �� Option C → Not the principal reason.
- �� Option D → Tetrahedral complexes still show orbital splitting.
Used
- Concept Recall
Application:
- �� Compare Δt with pairing energy.
Final Logic:
- �� Small Δt prevents electron pairing.
- Tetra = Tiny Splitting = High Spin
15 Arrange the following ligands in decreasing order of crystal field strength:
1. CO
2. NH₃
3. H₂O
4. Cl⁻
�� CO is a very strong-field ligand. �� NH₃ is stronger than H₂O. �� Cl⁻ is a weak-field ligand.
- According to the spectrochemical series: CO > NH₃ > H₂O > Cl⁻ → Therefore, the decreasing order of crystal field strength is: 1 > 2 > 3 > 4 → Hence, Option A is correct.
- �� Option B → Gives increasing order.
- �� Option C → Places NH₃ ahead of stronger CO.
- �� Option D → Places H₂O ahead of NH₃.
Used
- Ordering
Application:
- �� Recall the spectrochemical series from strongest to weakest.
Final Logic:
- �� CO > NH₃ > H₂O > Cl⁻.
- CO > NH₃ > H₂O > Cl⁻
16 For a d⁴ coordination entity, if Δo > P, what will be the resulting electronic configuration?
�� Δo > P indicates strong-field ligands. �� Electron pairing becomes favorable. �� A low-spin configuration forms.
- When Δo exceeds pairing energy, electrons prefer pairing in the lower-energy t₂g orbitals. → For a d⁴ system: t₂g⁴ eg⁰ → This represents a low-spin configuration. → Therefore, Option B is correct.
- �� Option A → Represents a high-spin d⁴ configuration.
- �� Option C → Violates Aufbau filling.
- �� Option D → Not possible under crystal field splitting.
Used
- Substitution
Application:
- �� Compare Δo and pairing energy.
Final Logic:
- �� Strong field → Low spin → t₂g⁴ eg⁰.
- Big Δ = Pair First
17 What happens when water is completely removed from [Ti(H₂O)₆]Cl₃ on heating?
�� Colour arises from d-d transitions. �� Ligands create crystal field splitting. �� Without ligands, visible-light absorption disappears.
- Water ligands create the crystal field responsible for d-orbital splitting. → Removal of all ligands eliminates crystal field splitting. → Without splitting, d-d transitions responsible for colour cannot occur. → Therefore, the compound becomes colourless. → Hence, Option B is correct.
- �� Option A → No stronger field is created.
- �� Option C → No ligand field remains.
- �� Option D → Charge transfer is not the reason.
Used
- Concept Recall
Application:
- �� Link colour with crystal field splitting.
Final Logic:
- �� No ligands → No splitting → No colour.
- No Ligands = No Colour
18 The yellow-red and blue absorption bands in emerald result in the transmission of which colour?
�� Absorbed colours are removed. �� Remaining transmitted light determines appearance. �� Emerald appears green.
- Emerald absorbs yellow-red and blue regions of the visible spectrum. → The remaining transmitted portion is predominantly green. → Therefore, emerald appears green. → Hence, Option C is correct.
- �� Option A → Red is largely absorbed.
- �� Option B → Yellow is absorbed.
- �� Option D → Violet is not the dominant transmitted colour.
Used
- Elimination
Application:
- �� Determine which colour remains after absorption.
Final Logic:
- �� Yellow-red and blue absorbed → Green transmitted.
- Emerald = Green
19 Identify the reaction type associated with the hypo solution in black and white photography:
�� Hypo solution contains thiosulfate. �� It dissolves unreacted AgBr. �� A soluble silver-thiosulfate complex is formed.
- Sodium thiosulfate ("hypo") is used as a fixing agent in photography. → It dissolves undecomposed AgBr by forming the soluble complex: [Ag(S₂O₃)₂]³⁻ → This removes excess silver bromide from the film. → Therefore, Option B is correct.
- �� Option A → Unrelated to photography.
- �� Option C → Refers to gold extraction.
- �� Option D → Refers to chelation therapy.
Used
- Concept Recall
Application:
- �� Recall the role of hypo in photographic fixing.
Final Logic:
- �� Hypo dissolves AgBr through complex formation.
- Hypo Fixes by Complexing Silver
20 Which chelating ligand is utilized in the medicinal treatment of lead poisoning?
�� EDTA is a hexadentate ligand. �� Forms stable complexes with Pb²⁺. �� Used in chelation therapy.
- EDTA strongly binds toxic lead ions through chelation. → The resulting stable complex is excreted from the body. → Therefore, EDTA is widely used in the treatment of lead poisoning. → Hence, Option C is correct.
- �� Option A → Mainly used for copper poisoning.
- �� Option B → Used for iron overload.
- �� Option D → Used as a reagent for nickel detection.
Used
- Concept Recall
Application:
- �� Recall medicinal applications of coordination compounds.
Final Logic:
- �� EDTA is the standard chelating agent for lead poisoning.
- EDTA Eliminates Lead
