NEET TEST SERIES 91 CHEMISTRY

1. The conductivity of 0.001028 mol L⁻¹acetic acid is 4.95×10−5 S cm⁻¹. Find out its dissociation constant if Λ⁰_m for acetic acid is 390.5 S cm⁻² mol⁻¹.

a) 2.18×10⁻⁵ mol⁻¹L⁻¹
b) 1.78×10⁻⁵ mol⁻¹L⁻¹
c) 3.72×10⁻⁴ mol⁻¹L⁻¹
d) 2.37×10⁻⁴ mol⁻¹L⁻¹

2. An unknown chlorohydrocarbon has 3.55% of chlorine. If each molecule of the hydrocarbon has one chlorine atom only, then chlorine atoms present in 1 g of chlorohydrocarbon are:
[Atomic wt. of Cl = 35.5 u; Avogadro constant =6.023×10²³mol⁻¹]

a) 6.023×10⁹
b) 6.023×10²³
c) 6.023×10²¹
d) 6.023×10²⁰

3. The rate constant of a reaction at 227⁰C and 427⁰C are 0.02 s⁻¹ and 0.2 s⁻¹. Calculate the activation energy of reaction.

a) 100 J
b) 300 J
c) 500 J
d) 700 J

4. The solubilities of AgCl in H₂O, 0.01M CaCl₂, 0.01 M NaCl and 0.05 M AgNO₃are denoted by S₁, S₂, S₃ and S₄ Which of the following relationships is correct?

a) S₁ > S₂ > S₃ > S₄
b) S₁ > S₃ > S₂ > S₄
c) S₁ > S₂ = S₃ > S₄
d) S₁ > S₃ > S₄ > S₂

5. 6 grams of magnesite mineral on heating liberated carbon dioxide which measures 1.12 L at STP. What is the percentage purity of mineral?

a) 50%
b) 60% 
c) 70%
d) 80%

6. The diagram given below is a vapour pressure-composition diagram for a binary solution of A and B
In the solution, A—B interactions are

a) similar to A—A and B—B interactions
b) greater than A—A and B— B interactions
c) smaller than A—A and B— B interactions
d) unpredictable

7. The solubility (S) of solute in water varies with temperature as given by S=Ae^−ΔH/RT , ΔH being the enthalpy of solution. For a given solute, variation of ln S with temperature is as shown in figure. The solute is expected to be


a) CaO
b) MgSO₄
c) CuSO₄
d) CuSO₄.5H₂O

8. 1g H₂gas STP is expanded so that the volume is doubled. Hence, work done is

a) 22.4 L -atm
b) 5.6 L -atm
c) 11.2 L -atm
d) 44.8 L -atm

9. Benzene burns according to the following equation at 300K (R=8.314 Jmol⁻¹K⁻¹)
2C₆H₆ (l) + 15O₂ (g) →12CO₂ (g) + 6H₂O (l); ΔH⁰ = − 6542kJ/mol
What is the ΔU for the combustion of  benzene at 25⁰C

a) – 6534 kJ
b) – 9813 kJ
c) – 4906.5 kJ
d) – 3271 Kj

10. Represent the cell in which the following reaction takes place
Mg (s) + 2Ag⁺ (0.0001 M) → Mg²⁺ (0.130M) +2Ag(s)
Calculate its E_(cell) if E⁰_(cell) = 3.17 V

a) 2.959 V
b) 4.26 V
c) 12.2 V
d) 16.4 V

11. Which of the following statement is false?

a) Raoult’s law is obeyed only when solution is very dilute
b) Both Raoult’s law and Henry’s law law says that P α X
c) Increase in temperature decreases solubility of solid in liquid for endorthermic reaction
d) Increase in temperature inecreases solubility of solid in liquid for endorthermic reaction

12. The time needed for the completion of 2/3^rd of a 1^st order reaction, when rate constant is 771×10⁻² min⁻¹ is

a) 23.03 min
b) 2.303 min
c) 6.93 min
d) 69.3 min

13. The equilibrium constant for the reversible reaction, N₂ (g) + 3H₂ (g) ⇌ 2NH₃ (g) is K and for reaction  1/2 N₂ (g) + 3/2 H₂ (g) ⇌ NH₃ (g), the equilibrium constant is K’, where K and K’ are related as:

a) K x K’ = 1
b) K = K’
c) K’ = √K
d) K = √K’

14. For a zero order reaction 2A ⇢ P, t_1/2 = 120 s and its initial concentration is 2 M. Calculate its rate constant

a) 1/240 mol^-1s^-1
b) 1/170 mol^-1s
c) 1/120 mol^-1s^-1
d) 1/80 mol^-1s^-1

15. In a solvent 50% of benzoic acid dimerises while rest ionises, determine molar mass of acid which is observed and also its van’t Hoff factor.

a) (Molar mass of acid)_cal > (Molar mass of acid)_obs, i = 4.21
b) (Molar mass of acid)_cal > (Molar mass of acid)_obs, i = 1.25
c) (Molar mass of acid)_obs > (Molar mass of acid)_cal, i = 4.21
d) (Molar mass of acid)_obs > (Molar mass of acid)_cal, i = 1.25

16. Which one of the following processes proceeds with the absorption of energy ?

a) Cl + e^– → Cl-
b) F + e^– → F-
c) O^– + e^– → O^2-
d) O + e^– → O-

17. Which of the following statements are not correct ?

a) Gallium wes earlier called eka –aluminium
b) 4^th period begins with Rubidium
c) 14 elements of 6^th period are called Lanthanoids
d) Henry Moseley discovered the relationship between X-ray spectra and atomic number of the elements.

18. Which of the following molecules have the highest Dipole moment ?

a) HCl
b) HF
c) H₂O
d) H₂

19. Choose the incorrect statement regarding Hybridisation ?

a) The type of Hybridisation indicates the geometry of the molecule.
b) The hybridized orbitals are always equivalent in energy and shape.
c) Promotion of electrons is not essential condition prior to hybridization.
d) In dsp³ hybridization the orbital uses in d is d_z²

20. Bond order of CO⁺ is

a) 2
b) 2.5
c) 3
d) 3.5