GATE XL exam:gate PYQs & Answers — Page 76

Questions 751–760 of 1235. Imported answers require independent review unless marked reviewed.

The correct order of the first ionization energies of He, B, N and O in their corresponding ground state is

Your answerChoose one option.

He > N > O > B

O > N > B > He

He > B > N > O

N > O > B > He

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Based on the molecular orbital theory, which one of the following statements with respect to N

, N

, O

and O

is correct?

Your answerChoose one option.

Bond orders of N

and O

are higher than their corresponding cations.

Bond energy of N

is higher than that of N

, whereas bond energy of O

is lower than that of O

The unpaired electrons in N

and O

are present in

and

orbitals, respectively.

The bond in N

is shorter than that in N

, whereas bond in O

is shorter than that in O

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Which one of the following statements is incorrect about the diborane molecule?

Your answerChoose one option.

B-H

bond is a 2-centre-2-electron bond (H

: terminal hydrogen).

B-H

bond is a 3-centre-2-electron bond (H

: bridge hydrogen).

The bond angle H

is 122° (H

: terminal hydrogen).

The B-H

bond distance is longer than B-H

bond distance (H

: terminal hydrogen, H

: bridge hydrogen).

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Given below are Newman projections of ethylene glycol and 1,2-difluoroethane about their respective C-C bonds. The most stable conformations (lowest energy) of ethylene glycol and 1,2-difluoroethane are

Your answerChoose one option.

I and II respectively.

I and IV respectively.

II and III respectively.

II and IV respectively.

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In the reaction given below, choose the condition that gives an anti-Markovnik’s product.

Your answerChoose one option.

Peroxide / HCl

Aqueous mercuric acetate treatment

Diborane addition

Sulfuric acid addition

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Which one of the following hexoses will give an osazone that has a different melting point from that of the osazone obtained from D (+) glucose?

Your answerChoose one option.

Diagram for Life Sciences question 11 (figure 2)

Diagram for Life Sciences question 11 (figure 3)

Diagram for Life Sciences question 11 (figure 4)

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A molecule in solution crystallizes into two different crystal forms with rate constants of 0.02 s

and 0.13 s

. If the crystallization is assumed to be under kinetic control, then the half-life (in seconds, rounded off to one decimal place) of the molecule is _________.

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The standard potential (

) for a cell reaction given below is +0.7 V. The standard reaction free energy (

) for this cell is ______ kJ mol

(correct up to two decimal places). (Given: Faraday constant, F = 96500 C mol

)

(aq) + 3 Ag (s)

Au (s) + 3 Ag

(aq)

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The activation energy (

) estimated for a reaction from the Arrhenius equation is 21 kJ mol

. If the frequency factor is assumed to be independent of temperature, then the ratio of the rate constants determined at 298 K and 260 K is ________ (rounded off to two decimal places). (Given: Gas constant, R = 8.315 J K

mol

)

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At a given pressure, a substance is heated from 2000 K to 2600 K. If the entropy of the substance is 60 J K

mol

, and is assumed to be constant over the given temperature range, then the change in the chemical potential (in kJ mol

) of the substance is ____________.

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GATE XL exam:gate PYQs

Question 6

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Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

Question 15