Which of the following compounds will give a positive Tollens test?
Answer: B
Tollens test is positive for aldehydes. Propanal (CH₃CH₂CHO) is an aldehyde and gets oxidized to carboxylic acid, reducing Ag⁺ to Ag (silver mirror). Acetone is a ketone, ether and alcohol do not give positive test.
Q.62Easy
Which of the following is the correct IUPAC name for the compound CH₃-CHBr-CH₂-CH₃?
Answer: A
The parent chain is butane (4 carbons). Numbering from the end nearest to substituent gives Br at position 2. IUPAC name is 2-bromobutane. Option D is a common name.
Q.63Easy
Which of the following is the correct order of atomic radius?
Answer: B
Atomic radius increases down a group in the periodic table. As we go from Na to K to Rb to Cs, the number of shells increases, leading to increased atomic radius.
Q.64Easy
Which of the following elements forms the most stable hydride?
Answer: B
Fluorine forms HF which is the most stable hydride among halogens due to the strong H-F bond (high bond energy ~570 kJ/mol), resulting from fluorine's high electronegativity.
Q.65Easy
Which of the following oxides is amphoteric?
Answer: B
Al₂O₃ is amphoteric, reacting with both strong acids (forming AlCl₃) and strong bases (forming aluminate ions). Na₂O is basic, SiO₂ is acidic, and P₂O₅ is acidic.
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Q.66Easy
Which of the following has the highest electronegativity value?
Answer: B
Fluorine has the highest electronegativity value (4.0 on Pauling scale) among all elements due to its small size and high nuclear charge.
Q.67Easy
Which statement about nitrogen oxides is incorrect?
Answer: C
N₂O₄ is colorless gas, not blue. NO is colorless, NO₂ is brown/reddish-brown, and N₂O is indeed called laughing gas.
Q.68Easy
Which of the following is not a property of noble gases?
Answer: A
Noble gases have VERY HIGH ionization energies (not low) due to their stable electron configuration. All other options are correct properties of noble gases.
Q.69Easy
The coordination number of Cu²⁺ in CuSO₄·5H₂O is:
Answer: B
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.70Easy
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.71Easy
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.72Easy
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.73Easy
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.
Q.74Easy
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.75Easy
What is the coordination number of zinc in [Zn(CN)₄]²⁻?
Answer: B
Zinc has a coordination number of 4 in this complex as four cyanide ligands are bonded to it. This follows the typical tetrahedral geometry for Zn²⁺.
Q.76Easy
Which metal exhibits variable oxidation states primarily due to incomplete d-orbital filling?
Answer: B
Iron (Fe) exhibits variable oxidation states (+2 and +3) due to its incomplete d-orbitals, allowing electron transitions between different oxidation states.
Q.77Easy
The white precipitate formed when AgNO₃ is added to a solution containing Cl⁻ ions is:
Answer: B
AgCl is a white precipitate (Ksp = 1.8 × 10⁻¹⁰) formed due to the low solubility product of silver chloride.
Q.78Easy
The ionization energy generally increases across a period because:
Answer: B
Across a period, increasing nuclear charge more significantly affects ionization energy than the slight increase in shielding, causing IE to increase.
Q.79Easy
Which halogen has the lowest electronegativity?
Answer: D
Iodine has the lowest electronegativity among halogens (2.5) due to its largest atomic radius and furthest valence electrons from nucleus.
Q.80Easy
Which of the following compounds would exhibit hydrogen bonding?
Answer: B
HF exhibits hydrogen bonding between H (bonded to highly electronegative F) and lone pairs on F of adjacent molecules.
