Miscellaneous Objective_Phase_1

CHEMISTRY

 

1. The bond order of CO molecule on the basis of molecular orbital theory is

(A) 0 (B) 2

(C) 3 (D) 1

 

2. The most polar molecule is

(A) CCl4 (B) CHCl3

(C) CH3Cl (D) CH3OH

 

3. Equal volumes of 0.1 M AgNO3 and 0.2 M NaCl are mixed. The concentration of ions in the mixture will be

(A) 0.1 M (B) 0.05 M

(C) 0.2 M (D) 0.15 M

 

4. Which one represents and impossible arrangement

n  m s n  m s

(A) 3 2 -2 1/2 (B) 4 0 0 1/2 

(C) 3 2 -3 1/2 (D) 5 3 0 1/2

 

5. The angular momentum of electron in nth orbit is given by

(A) nh (B) h/2πn

(C) nh/2π (D) n2h/2π

 

6. The ratio of the energy of a photon of 2000 Å wavelength radiation to that of 4000 Å radiation is

(A) 1/4 (B) 1/2

(C) 2 (D) 4

 

7. The ratio between root mean square velocity of H2 at 50K and that of O2 at 800K is

(A) 4 (B) 2

(C) 1 (D) 1/4

 

8. The energy in joule of a photon of light with wavelength 4 × 103 nm is

(A) 7.5 × 10-20 (B) 5 × 10-20

(C) 2 × 10-10 (D) 2.5 × 10-10

 

9. A gaseous mixture contains 1g of H2, 4g of He, 7g of N2 and 8g of O2. The gas having the highest partial pressure is

(A) H2 (B) O2

(C) He (D) N2

 

10. Which of the following bonds is most stable 

(A) 1s–1s (B) 2p–2p

(C) 2s–2p (D) 1s–2p

 

11. Number of electrons in 1.8ml of H2O is

(A) 6.02 × 1023 (B) 3.011 × 1023

(C) 0.6022 × 1023 (D) 60.22 × 1023

 

12. The rates of diffusion of O2 and H2 at same P and T are in the ratio

(A) 1 : 4 (B) 1 : 8

(C) 1 : 16 (D) 4 : 1

13. The highest excited state that unexcited hydrogen atoms can reach when they are bombarded with 12.2 eV photon is

(A) n = 1 (B) n = 2

(C) n = 3 (D) n = 4

 

14. The rms speed of hydrogen is times the rms speed of Nitrogen. If T is the temperature of the gas then

(A) (B)

(C) (D)

 

15. E1 for He+ is -54.4 eV. The E2 for He+ would be

(A) -6.8 eV (B) -13.6 eV

(C) -27.2 eV (D) -108.8 eV

 

16. The hybridization of atomic orbitals of Nitrogen in and are

(A) sp, sp3, sp2 (B) sp, sp2, sp3

(C) sp2, sp, sp3 (D) sp2, sp3, sp

 

17. The weight of 1mole of gas of density 0.1784g/lit at NTP is

(A) 0.1784g (B) 1g

(C) 4g (D) cannot be calculated

 

18. How many grams of KCl would have to be dissolved in 60 grams of H2O to give 20% by weight of solution

(A) 15g (B) 1.5g

(C) 11.5g (D) 31.5g

 

19. The bond length in and follows the order

(A) (B)

(C) (D)

 

20. 2 moles of ethyl alcohol are present with 6 moles of water. The mole fraction of alcohol is

(A) 0.5 (B) 0.75

(C) 0.15 (D) 0.25

 

21. If the pressure and temperature of 2 litre of CO2 are doubled, the volume of CO2 would become

(A) 5 litre (B) 4 litre

(C) 8 litre (D) 2 litre

 

22. The set having same number of s-electrons is

(A) C, Cu2+, Zn (B) Cu2+, Fe2+, Ni2+

(C) S2-, Ni2+, Zn (D) none

 

23. Decreasing order of size of various hybrid orbitals

(A) sp > sp2 > sp3 (B) sp3 > sp2 > sp

(C) sp2 > sp > sp3 (D) sp > sp3 > sp2

 

24. The pair of compounds having identical shape is 

(A) CF4, SF4 (B) PCl3, BF3

(C) XeF2, CO2 (D) PF5, IF5

25. The normality of 1% (wt./vol.) H2SO4 is nearly

(A) 0.02 (B) 0.2

(C) 0.1 (D) 1

 

26. If one litre of a gas A at 600mm and 0.5 litre of gas B at 800mm are taken in a 2 litre bulb. The resulting pressure is

(A) 1500mm (B) 1000mm

(C) 2000mm (D) 500mm

 

27. The wavelength of radiation emitted when electron falls from 4th Bohr’s orbit to 2nd in H atom is [RH = 1.09678 × 10-7m-1]

(A) 972 nm (B) 486 nm

(C) 243 nm (D) 182 nm

 

28. The molecule which has zero dipole moment is

(A) CH2Cl2 (B) BF3

(C) NF3 (D) ClO2

 

29. The weight of 350 ml of a diatomic gas at 0oC and 2 atm pressure is 1gram. The weight of one atom is

(A) 16/NA (B) 32/NA

(C) 16NA (D) 32NA

 

30. 0.44 g of a colourless oxide of Nitrogen occupies 224 ml at STP. The compound is

(A) N2O (B) NO

(C) N2O2 (D) NO2

 

31. At 100 oC and 1 atm, if the density of liquid water is 1.0 g cm-3 and that of water vapour is 0.0006 g cm–3, then the volume occupied by water molecules in one litre of steam at that temperature is

(A) 6 cm3 (B) 60 cm3

(C) 0.6 cm3 (D) 0.06 cm3

 

32. Bond order of anion is

(A) 3.0 (B) 2.0

(C) 2.5 (D) 1.5

 

33. A solution of HCl containing 0.03659 g/ml and another solution of acetic acid containing 0.04509 g/ml, then

(A) NHCl is more (B) is more

(C) Both have same N (D) None of these

 

34. An ion Mna+ has the magnetic moment equal to 4.9 B.M. The value of ‘a’ is

(A) 3 (B) 4

(C) 2 (D) 5

 

35. A gas will approach ideal behaviour at

(A) Low temperature and high pressure (B) Low temperature and low pressure

(C) High temperature and low pressure (D) High temperature and high pressure

 

36. On dissolving 1 mole each of the following acids in 1 litre water, the acid which does not give a solution of 1 N strength is

(A) HCl (B) HClO4

(C) HNO3 (D) H3PO4

37. AlCl3 is covalent while AlF3 is ionic. This is justified by

(A) crystal structure (B) valence bond theory

(C) Fajan’s rule (D) Lattice energy

 

38. The first emission line of Balmer series for H–spectrum has the wave number equal to

(A) (B)

 

(C) (D)

 

39. An ideal gas expands according to PV = constant. On expansion, the temperature of gas

(A) will rise (B) will drop

(C) will remain constant (D) cannot be determined because the external pressure is not known

 

40. The electronic configuration of an element is 1s22s22p63s23p63d54s1. This represents its

(A) Excited state (B) Ground state

(C) Cationic form (D) Anionic form

 

41. Among LiCl, BeCl2, BCl3 and CCl4, the covalent bond character varies as

(A) LiCl < BeCl2 < BCl3 < CCl4 (B) LiCl > BeCl2 < BCl3 < CCl4

(C) LiCl < BCl3 < BeCl2 < CCl4 (D) LiCl > BeCl2 > BCl3 > CCl4

 

42. A gas can be easily liquefied

(A) when its inversion temperature equals the Boyle temperature.

(B) under adiabatic compression

(C) under pressure when it is cooled to below the critical temperature.

(D) at low pressure and above the critical temperature.

 

43. The normality of 0.3 M phosphorous acid (H3PO3) is 

(A) 0.1 (B) 0.9

(C) 0.3 (D) 0.6

 

44. Total energy of 1 mole of an ideal gas (monoatomic) at 27 oC is

(A) 600 cal (B) 900 cal

(C) 800 cal (D) 300 cal

 

45. A hydrogen atom in its ground state absorbs a photon. The maximum energy of such a photon is

(A) 1.5 eV (B) 3.4 eV

(C) 10.2 eV (D) 13.6 eV

 

46. 34 g of hydrogen peroxide is present in 1120 ml solution. This solution is called

(A) 10 vol. solution (B) 20 vol. solution

(C) 30 vol. solution (D) 32 vol. solution

 

47. Hybridisation state of I in is

(A) dsp2 (B) sp

(C) sp2 (D) sp3

 

48. At a given temperature and pressure, the rate of diffusion of a gas is

(A) directly proportional to the density of the gas

(B) directly proportional to the square root of its density

(C) inversely proportional to the density of the gas

(D) inversely proportional to the square root of its density

49. What transition in He+ ion shall have the same wave number as the first line in Balmer series of hydrogen atom

(A) 3 ⎯→ 2 (B) 6 ⎯→ 4

(C) 5 ⎯→ 3 (D) 7 ⎯→ 5

 

50. The volume of 0.25 M H3PO4 required to neutralize 25 ml of 0.03 M Ca(OH)2 is

(A) 1.32 ml (B) 13.2 ml

(C) 26.4 ml (D) 2.0 ml

 

ANSWERS

 

1. C 2. D
2. B 4. C

5 C 6. C

7. C 8. B
8. C 10. A
9. A 12. A
10. C 14. C
11. B 16. B
12. C 18. A
13. A 20. D
14. D 22. B
15. B 24. C
16. B 26. D
17. B 28. B
18. A 30. A
19. C 32. C
20. A 34. A
21. C 36. D
22. C 38. D
23. C 40. B
24. C 42. C
25. D 44. B
26. D 46. A
27. D 48. D
28. B 50. D

 

HINTS & SOLUTION

 

1. Bond order = (Bonding electrons – anti bonding electrons)

 

3. mM of AgNO3 = 0.1V

mM of NaCl = 0.2V

∴mM of = 0.1V

or = 0.05

 

4. For  = 2, m cannot have a value of -3

 

5. E =

 

7. u(rms)H2 =

u(rms)O2 =

= 1

 

8. E =

 

9. P′ = mole fraction × Pm

The gas having higher mole fraction has high partial pressure.

 

10. More close are the shells to the nucleus, more is the extent of overlapping, stronger is the bond.

 

12.

 

13. E1 = -13.6eV

After absorption of 12.2 eV energy

EH = -13.6 + 12.2 = -1.4 eV

Now En = ∴n2 = = 9.71

n  ≈ 3

 

14. u(rms)H2 =
15. En =

E2 = = -13.6 eV

 

17. m =

 

18. % by wt. =

∴ 20 =

w = 15 gm

 

19. Bond length decreases with increase in bond order in diatomic molecule

 

20. Mole fraction = = 0.25

 

21.

 

23. An increase in s-character gives rise to a decrease in size of orbitals.

 

24. Both XeF2 (sp3d) and CO2(sp) are linear molecules.

 

25. N = = 0.2

 

26. Using PV = nRT, find n for A and B separately. For the mixture, taking V = 2 litre. Use
    PV = nRT

 

29. M = and then M g = 2 N atoms = N molecules. Thus, the gas is diatomic.

 

31. Mass of 1 litre water vapour = vol = 1000 × 0.0006 = 0.6 g

volume of water (liq) = 0.6 cm3

 

32. B.O = (Bonding electrons – antibonding electrons)

 

33. NHCl = = 1.002 N

= 0.7515 N

 

34. Magnetic moment = where n is the number of unpaired electrons.

4.9 =  

n = 4

36. H3PO4 is tribasic acid and thus N = M × basicity

 

38.

n1 = 2 for Balmer series

n2 = 3 for first line or Hα line of Balmer series

 

43. H3PO3 is a diabasic acid, thus

N = 2 M = 2 × 0.3 = 0.6

 

44. K.E. = = 900 cal mol-1

 

46. Amount of H2O2 in 1 ml = gm

∴gm H2O2 = litre O2 = 10 ml O2

 

48. r ∝ (at constant P and T)
49. E3 – E2 for H = ∴En =

E6 – E4 for He+ =

 

50. Meq. of H3PO4 = Meq. of Ca(OH)2

0.25 × 3V = 25 × 0.03 × 2

∴ V= 2 ml

 

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