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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

 

  1. The most polar molecule is

(A) CCl4 (B) CHCl3

(C) CH3Cl (D) CH3OH

 

  1. 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

 

  1. 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

 

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

(A) nh (B) h/2πn

(C) nh/2π (D) n2h/2π

 

  1. 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

 

  1. 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

 

  1. 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

 

  1. 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

 

  1. Which of the following bonds is most stable 

(A) 1s–1s (B) 2p–2p

(C) 2s–2p (D) 1s–2p

 

  1. 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

 

  1. 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

  1. 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

 

  1. 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)

 

  1. 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

 

  1. 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

 

  1. 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

 

  1. 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

 

  1. The bond length in and follows the order

(A) (B)

(C) (D)

 

  1. 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

 

  1. 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

 

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

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

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

 

  1. Decreasing order of size of various hybrid orbitals

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

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

 

  1. The pair of compounds having identical shape is 

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

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

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

(A) 0.02 (B) 0.2

(C) 0.1 (D) 1

 

  1. 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

 

  1. 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

 

  1. The molecule which has zero dipole moment is

(A) CH2Cl2 (B) BF3

(C) NF3 (D) ClO2

 

  1. 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

 

  1. 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

 

  1. 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

 

  1. Bond order of anion is

(A) 3.0 (B) 2.0

(C) 2.5 (D) 1.5

 

  1. 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

 

  1. 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

 

  1. 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

 

  1. 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

  1. 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

 

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

(A) (B)

 

(C) (D)

 

  1. 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

 

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

(A) Excited state (B) Ground state

(C) Cationic form (D) Anionic form

 

  1. 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

 

  1. 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.

 

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

(A) 0.1 (B) 0.9

(C) 0.3 (D) 0.6

 

  1. 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

 

  1. 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

 

  1. 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

 

  1. Hybridisation state of I in is

(A) dsp2 (B) sp

(C) sp2 (D) sp3

 

  1. 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

  1. 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

 

  1. 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

  1. C 8. B
  2. C 10. A
  3. A 12. A
  4. C 14. C
  5. B 16. B
  6. C 18. A
  7. A 20. D
  8. D 22. B
  9. B 24. C
  10. B 26. D
  11. B 28. B
  12. A 30. A
  13. C 32. C
  14. A 34. A
  15. C 36. D
  16. C 38. D
  17. C 40. B
  18. C 42. C
  19. D 44. B
  20. D 46. A
  21. D 48. D
  22. B 50. D

 

HINTS & SOLUTION

 

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

 

  1. mM of AgNO3 = 0.1V

mM of NaCl = 0.2V

mM of = 0.1V

or = 0.05

 

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

 

  1. E =

 

  1. u(rms)H2 =

u(rms)O2 =

= 1

 

  1. E =

 

  1. P = mole fraction × Pm

The gas having higher mole fraction has high partial pressure.

 

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

 

12.

 

  1. E1 = -13.6eV

After absorption of 12.2 eV energy

EH = -13.6 + 12.2 = -1.4 eV

Now En = n2 = = 9.71

3

 

  1. u(rms)H2 =
  2. En =

E2 = = -13.6 eV

 

  1. m =

 

  1. % by wt. =

20 =

w = 15 gm

 

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

 

  1. Mole fraction = = 0.25

 

21.

 

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

 

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

 

  1. N = = 0.2

 

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

 

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

 

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

volume of water (liq) = 0.6 cm3

 

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

 

  1. NHCl = = 1.002 N

= 0.7515 N

 

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

4.9 =  

n = 4

  1. 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

 

  1. H3PO3 is a diabasic acid, thus

N = 2 M = 2 × 0.3 = 0.6

 

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

 

  1. Amount of H2O2 in 1 ml = gm

gm H2O2 = litre O2 = 10 ml O2

 

  1. r (at constant P and T)
  2. E3 – E2 for H = En =

E6 – E4 for He+ =

 

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

0.25 × 3V = 25 × 0.03 × 2

V= 2 ml

 

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