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 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 .


2.

Heisenberg's uncertainty principle can beexplained as :

  •  p × h4π

  • x x  h4π

  • x x  hπ

  •  πhx


B.

x x  h4π

Heisenberg's uncertainty principle : It is notpossible to determine precisely both theposition and the momentum (or velocity) of asmall moving particle (e.g , electron , proton etc)

x .ph4π

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


3.

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


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 strongbase is always close to 13.7 kcal .

HAstrongacid+BOHstrongbaseH2O + AB

H = - 13.7 Kcal

The heat of neutralisation of strong acid andstrong base is actually the heat of formation of1 gmole of water from 1 g of H+ and 1 g of OH- .


5.

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


6.

The solubility product of Mg(OH)2 at 25°C is1.4 x 10-11 .What is the solubility of Mg(OH)2in 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)2Mg2+ + 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


7.

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 .


8.

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 energyreleased when two atoms get bonded or it isequal to the energy required to break the bondto form the neutral atoms .

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


9.

The heat of formarion of CO2 is - 393 kJ mol-1 .The amount of heat evolved in the formation of0.156 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 ofCO2= - 93kJ

Heat evolved in the formation of 0.156 kgof CO2

=-393×15644

= - 1393 kJ


10.

The magnitude of orbital angular momentum ofan 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