Subject

Chemistry

Class

NEET Class 12

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

 Multiple Choice QuestionsMultiple Choice Questions

1.

The magnitude of orbital angular momentum of an electron of azimuthal quantum number 2 is :

  • 2h2π

  • 6h2π

  • 2h2π

  • 6h2π


B.

6h2π

Orbital angular momentum = l (l + 1 ) h2π

where l = azimuthal quantum number

6h2π


2.

What is the frequency of a X-ray photon whose momentum is 1.1 x 10-23 kg-ms-2 ?

  • 5 x 1016 Hz

  • 0.5 x 1027 Hz

  • 0.5 x 1018 Hz

  • 5 x 1018 Hz


D.

5 x 1018 Hz

E = mc2

E = hv

mc2 = hv

ν = mc2h = 1.1 × 10-23 × 3 × 1086.6 × 10-34

= 5  x 1018 Hz


3.

The solubility product of Mg(OH)2 at 25°C is 1.4 x 10-11 .What is the solubility of Mg(OH)2 in g/L ?

  • 0.0047 g/L

  • 0.047 g/L

  • 0.0087 g/L

  • 0.087 g/L


C.

0.0087 g/L

Mg(OH)2  Mg2+ + 2OH-

Ksp = [Mg2+][OH-]2

1.4 X 10-11 = (s)(2s)2

1.4 X 10-11 = 4s3

s = 1.5 x 10-4 mol/L

(Mol. wt. of Mg(OH)2 = 52)

= 58 X 1.5 x 10-4

= 0.0087 g/L


4.

Heat of neutralisation of an acid with a base is 13. 7 kcal when :

  • both acid and base are weak

  • acid is weak and base is strong

  • both acid and base are strong

  • acid is strong and base is weak


C.

both acid and base are strong

Heat of neutralisation for strong acid and strong base is always close to 13.7 kcal .

HAstrong acid + BOHstrong base  H2O + AB

H = - 13.7 Kcal

The heat of neutralisation of strong acid and strong base is actually the heat of formation of 1 gmole of water from 1 g of H+ and 1 g of OH- .


5.

Hess's law is based on :

  • law of conservation of mass

  • law of conservation of energy

  • enthalpy is a state function

  • none of the above


B.

law of conservation of energy

Hess's law is based upon conservation of energy .


6.

The geometry of methane molecule is :

  • tetrahedral

  • pyramidal

  • octahedral

  • square planar


A.

tetrahedral

Methane (CH3) shows the sp3 hybridisation .So , the geometry of methane molecule is tetrahedral .


7.

The bond energy is the energy required to :

  • dissociate one mole of the substance

  • dissociate bond in 1 kg of the substance

  • break one mole of similar bonds

  • break bonds in one mole of the substance


C.

break one mole of similar bonds

Bond energy : It may be defined as the energy released when two atoms get bonded or it is equal to the energy required to break the bond to form the neutral atoms .

e.g , H-H (g)  H + H , H = + 103 Kcal/mol


8.

The heat of formarion of CO2 is - 393 kJ mol-1 .The amount of heat evolved in the formation of 0.156 kg of CO2 .

  • - 1393 kJ

  • + 1165.5 kJ

  • + 1275.9 kJ

  • - 1165.5 kJ


A.

- 1393 kJ

 Heat evolved during the formation of 44 g of CO2 = - 93kJ

 Heat evolved in the formation of 0.156 kg of CO2

=- 393 × 15644

= - 1393 kJ


9.

Heisenberg's uncertainty principle can be explained as :

  •  p × h4π

  • x x  h4π

  • x x  hπ

  •  πhx


B.

x x  h4π

Heisenberg's uncertainty principle :  It is not possible to determine precisely both the position and the momentum (or velocity) of a small moving particle (e.g , electron , proton etc)

x .  h4π

where x , p are the uncertainties with regard to position , momentum respectively .


10.

The pH of a 0.02 M solution of HCl is :

  • 2.2

  • 2.0

  • 0.3

  • 1.7


D.

1.7

0.02 M HCl = 2 x 10-2 M HCl

[H+] = 2 x 10-2

pH = - log[H+]

= - log [2 x 10-2]

= - log 2 + 2 log 10

= - 0.3010 + 2

= 1.7