Cu²⁺ is surrounded by 4 water molecules in the coordination sphere and 2 more from the sulfate ion or additional water molecules, giving octahedral geometry with coordination number 6.
Q.22Easy
Which of the following d-block elements has the configuration [Ar]3d¹⁰4s¹?
Answer: A
Copper has atomic number 29 with configuration [Ar]3d¹⁰4s¹. It exhibits anomalous behavior by having a completely filled d-orbital.
Q.23Easy
The hybridization of sulfur in SF₆ molecule is:
Answer: C
SF₆ has 6 bonding pairs around sulfur with no lone pairs, requiring sp³d² hybridization for octahedral geometry.
Q.24Easy
The bond angle in PCl₃ is approximately:
Answer: B
PCl₃ has trigonal pyramidal geometry with one lone pair on phosphorus. Bond angle is approximately 107° due to lone pair repulsion.
Q.25Easy
The oxidation state of Mn in KMnO₄ is:
Answer: C
In KMnO₄, K is +1, O is -2, so Mn is +7. This makes permanganate a strong oxidizing agent.
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Q.26Medium
Which statement about diagonal relationship in periodic table is correct?
Answer: C
Be and Al show diagonal relationship due to similar charge-to-radius ratio. Both form covalent compounds and amphoteric oxides.
Q.27Medium
The most stable oxidation state of chromium is:
Answer: B
+3 is the most stable oxidation state for Cr with d³ configuration. Cr³⁺ complexes are highly stable.
Q.28Medium
In the reaction of P₄ with excess oxygen, the product is:
The orange color arises from charge transfer between oxygen and chromium, not from d-d transition within Cr³⁺.
Q.30Medium
Which of the following metals can displace hydrogen from dilute acids?
Answer: C
Zn is more reactive than hydrogen and can displace it from dilute acids. Cu, Ag, and Au are less reactive than hydrogen.
Q.31Medium
The aqueous solution of which salt would be basic?
Answer: C
Na₂CO₃ solution is basic because CO₃²⁻ hydrolyzes to produce OH⁻ ions. It's the salt of weak acid and strong base.
Q.32Medium
Which complex ion shows maximum paramagnetism?
Answer: C
[CoF₆]³⁻ is high spin with 4 unpaired electrons (d⁶). [Fe(CN)₆]⁴⁻ is low spin with 0 unpaired electrons. [Fe(H₂O)₆]²⁺ has 4 unpaired electrons but [CoF₆]³⁻ has higher magnetic moment.
Q.33Medium
The lattice energy of NaCl is higher than that of NaI because:
Answer: B
Lattice energy is inversely proportional to interionic distance. Cl⁻ is smaller than I⁻, so NaCl has higher lattice energy.
Q.34Hard
The stability of peroxides and superoxides of alkali metals increases with increasing atomic number because:
Answer: A
Larger alkali metal cations (K⁺, Rb⁺) can stabilize larger peroxide and superoxide anions due to better lattice energy matching.
Q.35Hard
In the extraction of iron from Fe₂O₃ using CO as reducing agent, the rate-determining step involves:
Answer: B
In solid-state reduction, diffusion through the ash layer is often the rate-determining step, creating a diffusion barrier.
Q.36Hard
Which of the following chromium compounds would show maximum paramagnetic behavior?
Answer: A
[Cr(H₂O)₆]³⁺ is high spin with 3 unpaired electrons. CN⁻ is strong field ligand causing pairing. [Cr(NH₃)₆]³⁺ is intermediate.
Q.37Hard
The structure of [PtCl₄]²⁻ is square planar because:
Answer: D
Pt²⁺ has d⁸ configuration. With strong field Cl⁻, square planar geometry provides maximum CFSE and is thermodynamically favored.
Q.38Medium
Which of the following elements forms the most stable +6 oxidation state compound?
Answer: B
Molybdenum forms very stable +6 oxidation state compounds like MoO₃ and MoO₄²⁻. This is due to d-block stability and orbital availability.
Q.39Easy
In the thermite reaction, which metal is oxidized?
Answer: C
In the thermite reaction (2Al + Fe₂O₃ → Al₂O₃ + 2Fe), aluminum is oxidized from 0 to +3 oxidation state as it reduces Fe₂O₃.
Q.40Medium
Which halide of boron exists as a dimer in the gaseous state?
Answer: B
BCl₃ forms a dimer (B₂Cl₆) in gaseous state due to bridging chlorine atoms. BF₃ remains monomeric due to strong B-F bonds and p-p repulsion.
