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.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

Advertisement

31.

Assertion : Staggered conformation of ethane is 12.5 kJ mol-1 more stable than the eclipsed conformation.

Reason : The two conformations of ethane cannot be separated at room temperature.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


B.

If both assertion and reason are true but reason is not the correct explanation of assertion

Staggered conformation is more stable because in this conformation any two hydrogen atoms on adjacent carbon atoms are as far apart as possible and the repulsion between the electron clouds of σ- bonds of two non-bonded hydrogen atoms is minimum.

The energy difference of 12.55 kJ mol-1 is not large enough to prevent rotation at room temperature as a result it is not possible to seperate the two conformations of ethane.


Advertisement
32.

Assertion : The Dumas method is more applicable to nitrogen containing organic compounds than the Kjeldahl's method.

Reason: The Kjeldahl's method does not give satisfactory results for compounds in which nitrogen is directly linked to oxygen.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion.

  • If assertion is true but reason is false

  • If both assertion and reason are false


33.

How many Faradays of electricity are required for the given reaction to occur ?

MnO4- Mn2+

  • 5 F

  • 3 F

  • 1 F

  • 7 F


34.

Paints and hair creams are respectively

  • sol and emulsion

  • aerosol and foam

  • emulsion and sol

  • foam and gel.


Advertisement
35.

Chlorine oxidises sodium thiosulphate to form

  • Na2SO3

  • Na2O

  • Na2SO4

  • Na2CO3


36.

Large difference in boiling points is observed in

  • N and P

  • P and As

  • As and Sb

  • Sb and Bi


37.

Arrange the given compounds in decreasing order of boiling points.

I. CH3CH2CH2CH2Br

II. C(CH3)3Br

III. CH3-CH2-CH(CH3)-Br

  • I > III > II

  • II > I > III

  • I > II > III

  • III > I > II


38.

If an atom crystallises in bee lattice with r= 4 Å then the edge length will be

  • 2 Å

  • 8 Å

  • 2.39 Å

  • 9.23 Å


Advertisement
39.

A first order reaction, which is 30% complete in 30 minutes has a half-life period of

  • 102.2 min

  • 58.2 min

  • 24.2 min

  • 120.2 min


40.

Two elements A and B form compounds of formula AB2 and AB4. When dissolved in 20.0 g of benzene 1.0 g of AB2 lowers freezing point by 2.3°C whereas 1.0 g of AB4 lowers freezing point by 1.3°C. The Kf for benzene is 5.1. The atomic masses of A and B are

  • 25, 42

  • 42, 25

  • 52, 48

  • 48, 52


Advertisement