Q1. A non-stoichiometric sample of nickel oxide has the formula Ni₀.₉₆O₁.₀₀. To maintain electrical neutrality, a certain percentage of Ni²⁺ ions are replaced by Ni³⁺ ions. What is the approximate percentage of Ni²⁺ ions in this crystal lattice?
Correct Answer: Option A (96%)
Explanation: Detailed explanation will be updated shortly.
Q2. Consider two aqueous solutions: Solution A is 0.1 m Ba(NO₃)₂ and Solution B is 0.15 m Glucose (C₆H₁₂O₆). Assuming complete dissociation for the strong electrolyte, which statement correctly describes the relationship between their freezing points (T_f)?
Correct Answer: Option A (T_f (A) < T_f (B))
Explanation: Detailed explanation will be updated shortly.
Q3. For the galvanic cell: Zn(s) | Zn²⁺(aq, 1M) || Cu²⁺(aq, 1M) | Cu(s), what would be the qualitative effect on the cell EMF if a few drops of a concentrated Na₂S solution were added to the cathode compartment?
Correct Answer: Option A (EMF will increase significantly.)
Explanation: Detailed explanation will be updated shortly.
Q4. For a zero-order reaction, the time taken for 50% completion is 't'. What will be the time required for the reaction to go to 80% completion?
Correct Answer: Option A (1.6 t)
Explanation: Detailed explanation will be updated shortly.
Q5. Which of the following pairs of isomerism is NOT exhibited by the coordination complex [Cr(en)₂(NH₃)Br]Cl₂? (en = ethane-1,2-diamine)
Correct Answer: Option A (Geometrical and Optical Isomerism)
Explanation: Detailed explanation will be updated shortly.
Q6. The reaction of benzaldehyde with a 50% aqueous NaOH solution results in the formation of sodium benzoate and benzyl alcohol. If a mixture of benzaldehyde and formaldehyde is subjected to the same conditions, which statement is correct?
Correct Answer: Option A (Benzaldehyde is oxidized to sodium benzoate and formaldehyde is reduced to methanol.)
Explanation: Detailed explanation will be updated shortly.
Q7. In the solid state, PCl₅ exists as an ionic solid. When it reacts with water, it gives two acids, 'X' and 'Y'. In contrast, PCl₃ on hydrolysis gives an acid 'Z' and acid 'Y'. What are X, Y, and Z respectively?
Correct Answer: Option A (X = H₃PO₄, Y = HCl, Z = H₃PO₃)
Explanation: Detailed explanation will be updated shortly.
Q8. An organic compound 'A' (C₅H₁₀O) gives a positive 2,4-DNP test and a positive iodoform test, but a negative Tollens' test. On vigorous oxidation, it yields a mixture of ethanoic acid and propanoic acid. What is the structure of compound 'A'?
Correct Answer: Option A (Pentan-3-one)
Explanation: Detailed explanation will be updated shortly.
Q9. The lanthanoid contraction is responsible for many chemical consequences. Which of the following properties shows a steady increase across the lanthanoid series (from La to Lu)?
Correct Answer: Option A (Basicity of M(OH)₃)
Explanation: Detailed explanation will be updated shortly.
Q10. A bridged bicyclic halide, 1-chlorobicyclo[2.2.2]octane, is exceptionally unreactive towards both Sₙ1 and Sₙ2 reactions. The primary reason for its inertness towards Sₙ1 reaction is:
Correct Answer: Option A (Severe steric hindrance at the bridgehead carbon.)
Explanation: Detailed explanation will be updated shortly.
Q11. The coagulation of 100 mL of a negative sol (like As₂S₃) is achieved by adding 5 mL of 1 M NaCl solution. To cause the same coagulation for the same sol, 0.5 mL of a solution of electrolyte 'X' is required. What could be 'X'?
Correct Answer: Option A (K₂SO₄)
Explanation: Detailed explanation will be updated shortly.
Q12. Arrange the following compounds in the decreasing order of their pKₐ values: Phenol (I), p-Cresol (II), p-Nitrophenol (III), p-Methoxyphenol (IV).
Correct Answer: Option A (III > I > II > IV)
Explanation: Detailed explanation will be updated shortly.
Q13. In the froth flotation process for the separation of ZnS and PbS ores, NaCN is used as a:
Correct Answer: Option A (Froth stabilizer, to enhance the stability of the froth.)
Explanation: Detailed explanation will be updated shortly.
Q14. An aqueous solution containing a non-volatile solute has a boiling point of 100.52 °C. What will be the freezing point of this solution? (Given: K_b = 0.52 K kg mol⁻¹ and K_f = 1.86 K kg mol⁻¹ for water)
Correct Answer: Option A (-1.86 °C)
Explanation: Detailed explanation will be updated shortly.
Q15. Which of the following reagents can be used to distinguish between ethanamine and N-ethylethanamine but will react with both?
Correct Answer: Option A (Hinsberg's reagent (Benzenesulphonyl chloride))
Explanation: Detailed explanation will be updated shortly.
Q16. Consider the decomposition of a gaseous compound A: A(g) → 2B(g) + C(g). The reaction follows first-order kinetics. If the total pressure of the system was P₀ at t=0 and P_t at time 't', the correct expression for the rate constant 'k' is:
Correct Answer: Option A (k = (2.303/t) log [P₀ / (P_t - P₀)])
Explanation: Detailed explanation will be updated shortly.
Q17. Which of the following statements is incorrect regarding the comparison between Nylon 6,6 and Buna-S?
Correct Answer: Option A (Nylon 6,6 is a polyamide fibre, while Buna-S is a synthetic elastomer.)
Explanation: Detailed explanation will be updated shortly.
Q18. The magnetic moment of [Fe(H₂O)₆]²⁺ is 4.90 BM, while that of [Fe(CN)₆]⁴⁻ is 0. What is the most accurate explanation for this difference?
Correct Answer: Option A (H₂O is a weak field ligand causing high spin complex, while CN⁻ is a strong field ligand causing low spin complex.)
Explanation: Detailed explanation will be updated shortly.
Q19. Identify the product 'Z' in the following reaction sequence:
Aniline --(NaNO₂/HCl, 273K)--> X --(CuCN/KCN)--> Y --(H₂O/H⁺, Heat)--> Z
Correct Answer: Option A (Phenol)
Explanation: Detailed explanation will be updated shortly.
Q20. The standard reduction potential (E°) for the half-cell NO₃⁻(aq) / NO(g) in acidic solution is +0.96 V. Which of the following metals will NOT be oxidized by 1M HNO₃? (E° values are given)
Correct Answer: Option A (Ag⁺/Ag (+0.80 V))
Explanation: Detailed explanation will be updated shortly.