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.

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

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

Mn${\mathrm{O}}_4^{-} \to$Mn²⁺

• 5 F

• 3 F

• 1 F

• 7 F

Paints and hair creams are respectively

• sol and emulsion

• aerosol and foam

• emulsion and sol

• foam and gel.

Chlorine oxidises sodium thiosulphate to form

• Na₂SO₃

• Na₂O

• Na₂SO₄

• Na₂CO₃

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

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

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

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 K_f for benzene is 5.1. The atomic masses of A and B are

• 25, 42

• 42, 25

• 52, 48

• 48, 52