NEET TEST SERIES 157 CHEMISTRY

1. In the Friedel Craft’s acylation reaction, the effective electrophile is

(a) RCOCl⁺
(b) AIC1₃
(c) RCOCI
(d) RCO⁺

2. A reaction proceeds by first order, 75% of this reaction was completed in 32 min. The time required for 50% completion is (in minute)

(a) 8 
(b) 16
(c) 20    
(d) 24

3. Consider the following statements
I. The radius of an anion is larger than that of the parent atom.
II. The ionization energy generally increases with increasing atomic number in a period.
III. The electronegativity of an element is the tendency of an isolated atom to attract an electron.

Which of the above statements is/are correct?

(a) I alone
(b) II alone
(c) l and II
(d) II and III

6. In which of the following options the order of arrangement does not agree with the variation of property indicated against it ?

(a) Al³⁺ < Mg²⁺ < Na⁺ < F^– (increasing ionic size)
(b) B<C<O<N (increasing first ionisation enthalpy)
(c) I < Br < Cl < F (increasing electron gain enthalpy)
(d) Li<Na< K< Rb (increasing metallic radius)

7. Choose the correct stability order of group 13 elements in their + 1 oxidation state.

(a) Al < Ga < ln < TI
(b) Tl < ln < Ga < Al
(c) Al < Ga < TI < ln
(d) (d) A I<Tl < Ga < ln

8. Which one of the following group-15 hydrides is the strongest reducing agent?

(a) AsH₃
(b) BiH₃
(c) PH₃
(d) SbH₃

9. Haemoglobin contains 0.34% of iron by mass. The number of Fe atoms in 3.3 g of haemoglobin is: (Given: Atomic mass of Fe is 56u, N_A in 6.022×10²³ mol^-1 )

(a) 1.21 × 10⁵                       
(b) 12.0 × 10⁵
(c) 1.21 × 10²⁰                        
(d) 3.4 × 10²²

10. Statement I: Different number of electron pairs arc present in resonance structures.
      Statement II : Resonance structures do not differ in the location of electrons around the constituent atoms.

(a) Both statement I and II are correct.
(b) Both statement I and II are incorrect.
(c) Statement I is correct but statement II is incorrect.
(d) Statement II is correct but statement I is incorrect

11. The limiting molar conductivities of HCI, CH₃COONa and NaCI are respectively 425,90 and 125 mho cm² mol^-1 at 25°C. The molar conductivity of 0.1 M CH₃COOH solutions is  7.8 mho cm² mol^-1 at the same temperature. The degree of dissociation of 0.1 M acetic acid solution at the same temperature is

(a) 0.10
(b) 0.02
(c) 0.15
(d) 0.03  125 mho cm² mol^-1

12. Assertion: Protonation of a carbonyl group increases its electrophilic character.
      Reason: Protonation of a carbonyl group involves addition of an electrophile on nucleophilic oxygen.

(a) If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
(b) If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
(c) If the Assertion is correct but Reason is incorrect.
(d) If the Assertion is incorrect and Reason is correct.

13. Which of the following compounds shows optical isomerism?

14. 25.3 g of sodium carbonate, Na₂CO₃ is dissolved in enough water to make 250 mL of solution. If sodium carbonate dissociates completely, molar concentration of sodium ions, Na⁺ and carbonate ions, are respectively (Molar mass of Na₂CO₃ = 106 g mol^-1)

(a) 0.955 M and 1.910 M   
(b) 1.910M and 0.955 M
(c) l.90Mand I.910M
(d) 0.477 M and 0.477 M

15. In which alkyl halide, S_N2 mechanism is favoured maximum?

(a) CH₃CI
(b) CH₃CH₂CI
(c) (CH3)₂CHCI
(d) (CH₃)₃C-CI

16. Equilibrium constant K changes with temperature. At 300 K, equilibrium constant is 25 and at 400 K, it is 10. Hence, backward reaction will have energy of activation

(a) equal to that of forward reaction.
(b) less than that of forward reaction.
(c) greater than that of forward reaction.
(d) given values are not sufficient to explain given statement.