Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Class 11 Chemistry 35 Years JEE Mains &Advance Past yr Paper

JEE : Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

The document Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev is a part of the JEE Course Class 11 Chemistry 35 Years JEE Mains &Advance Past yr Paper.
All you need of JEE at this link: JEE

Q.1. The bond order and the magnetic characteristic of CN are    (2020)
(1) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev, diamagnetic

(2) 3, diamagnetic
(3) 3, paramagnetic
(4) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev, paramagnetic

Ans. (2)
The molecular electronic configuration of CN is:
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Since, there is no unpaired electron, thus, CN is diamagnetic in nature.

Q.2. According to molecular orbital theory, which of the following is true with respect to Li2+ and Li2-?    (2019)
(1) Li2+ is unstable and Li2- is stable
(2) Li2+ is stable and Li2- is unstable
(3) Both are stable
(4) Both are unstable
Ans.
(3)
Electronic configuratios of Li2+ and Li2-:
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Now,
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Here, both Li2+ and Li2- have positive bond order, thus both are stable.

Q.3. In which of the following processes, the bond order has increased and paramagnetic character has changed to diamagnetic?    (2019)
(1) NO → NO+    
(2) N→ N2+
(3) O→ O2+
(4) O→ O22-
Ans.
(1)
In case of NO (paramagnetic) → NO+ (diamagnetic) the bond order has increased from 2.5 to 3.
For other cases:
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
B.O = 2    B.O = 1

Q.4. Two pi and half sigma bonds are present in:     (2019)
(1) O2+
(2) N2
(3) O2
(4) N2+
Ans.
(4)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Q.5. Among the following molecules/ions,Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRevWhich one is diamagnetic and has the shortest bond length?    (2019)
(1) O2
(2) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev 

(3) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
(4) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Ans. (4)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
and diamagnetic species has no unpaired electron in their molecular orbitals.Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Q.6. Among the following, the molecule expected to be stabilized by anion formation is:    (2019)
C2, O2, NO, F2
(1) C2 
(2) F2 
(3) NO
(4) O2
Ans.
(1)
In case of only C2, incoming electron will enter in the bonding molecular orbital which increases the bond order and stability too. Whereas rest of all takes electron in their antibonding molecular orbital which decreases bond order and stability.

Q.7. Among the following species, the diamagnetic molecule is:    (2019)
(1) NO
(2) CO
(3) B2 
(4) O2
Ans.
(2)
The molecules with no unpaired electrons are diamagnetic.
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Since CO has no unpaired electron. Hence, CO is diamagnetic.

Q.8. During the change of O2 to O2- the incoming electron goes to the orbital:    (2019)
(1) π2py 
(2) σ*2pz 
(3) π*2py 
(4) π2px
Ans.
(3)
Electronic configuration of O2 is
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Q.9. The correct statement among the following is :    (2019)
(1) (SiH3)3N is planar and less basic than (CH3)5N.
(2) (SiH3)3N is pyramidal and more basic than (CH3)3N.
(3) (SiH3)3N is pyramidal and less basic than (CH3)3N.
(4) (SiH3)3N is planar and more basic than (CH3)3N.
Ans.
(1)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev 

Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Due to backbonding of lone pair electrons of nitrogen into vacant d-orbitals of Si, trisilylamine (SiH3)3N is planar. In trimethylamine (CH3)3N, there is no backbonding and hence it is more basic.

Q.10. According to molecular orbital theory, which of the following will not be a viable molecule?    (2018)
(1) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
(2) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
(3) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
(4) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Ans. 
(4)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Q.11. In graphite and diamond, the percentage of p-characters of the hybrid orbitals in hybridisation are respectively:    (2018)
(1) 67 and 75 
(2) 33 and 25 
(3) 50 and 75 
(4) 33 and 75 
Ans.
(1)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Graphite
Sp2 hybridization
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
= 67 %
Diamond
Sp3 hybridisation
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
= 75%

Q.12. Which of the following is a Lewis acid?    (2018)
(1) B(CH3)3 
(2) PH3 
(3) NaH 
(4) NF3 
Ans. 
(1)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Q.13. In the molecular orbital diagram for the molecular ion, N2+, the number of electrons in the σ2p molecular orbital is:    (2018)
(1) 1
(2) 3
(3) 0
(4) 2
Ans.
(1)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Q.14. Which of the following conversions involves change in both shape and hybridisation?    (2018)
(1) H2O → H3O+ 
(2) BF3 → BF4 
(3) CH4 →C2H6 
(4) NH3 → NH4+ 
Ans. (2)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRevPrevious year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Q.15. The most polar compound among the following is:     (2018)
(1) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
(2) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
(3) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
(4) Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
Ans.
(3)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
the bond dipole vector of C–F bond is not subtractive. 

Q.16. The incorrect geometry is represented by:     (2018)
(1) NF3 – trigonal planar 
(2) BF3 – trigonal planar 
(3) AsF– trigonal bipyramidal 
(4) H2O – bent 
Ans.
(1)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Q.17. Which of the following species is not paramagnetic?    (2017)
(1) NO 
(2) CO 
(3) O2 
(4) B2 
Ans.
(2)
CO has 14 electrons (even) ∴ It is diamagnetic
NO has 15e-(odd) ∴ It is paramagnetic and has 1 unpaired electron in π*2p molecular orbital. 
B2 has 10e- (even) but still paramagnetic and has two unpaired electrons in π2px and π2py (s-p mixing). 
O2 has 16 e- (even) but still paramagnetic and has two unpaired electrons in π*2px and π*2py molecular 

Q.18. Which of the following is paramagnetic?    (2017)
(1) CO
(2) NO+ 
(3)Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev 
(4) B2
Ans.
(4)
No of e in
CO = 14, NO+ = 14
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev  = 18,  B2 = 10
According to MOT
B2 is paramagnetic

Q.19. sp3d2 hybridization is not displayed by:    (2017)
(1) SF6
(2) BrF5
(3) PF5
(4) [CrF6]3-
Ans.
(3)
SF6 = Sp3d2   BrF= SP3d2
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev PF5 = sp3d

Q.20. The group having triangular planar structure is    (2017)
(1) BF3, NF3, CO32– 
(2) CO32–, NO3, SO3
(3) NH3, SO3, CO32– 
(4) NCl3, BCl3, SO3
Ans.
(2)
CO32–, NO3, SO: SP2 Hybridised

Q.21. The species in which the N atom is in a state of sp hybridization is:    (2016)
(1) NO2+ 
(2) NO2- 
(3) NO3- 
(4) NO2 
Ans.
(1)
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev
The lewis structure of NO2 shows a bent molecular geometry with trigonal planar electron pair geometry hence the hybridization will be sp2
Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

Q.22. Which one of the following statements about water is FALSE?    (2016)
(1) Water is oxidized to oxygen during photosynthesis. 
(2) Water can act both as an acid and as a base. 
(3) There is extensive intramolecular hydrogen bonding in the condensed phase. 

(4) Ice formed by heavy water sinks in normal water.
Ans. 
(3)
Water possess intermolecular hydrogen bonding in the condensed phase. 

Offer running on EduRev: Apply code STAYHOME200 to get INR 200 off on our premium plan EduRev Infinity!

Complete Syllabus of JEE

JEE

Dynamic Test

Content Category

Related Searches

practice quizzes

,

Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

,

Previous Year Questions with Solutions

,

Extra Questions

,

Objective type Questions

,

Free

,

Sample Paper

,

past year papers

,

video lectures

,

pdf

,

shortcuts and tricks

,

Semester Notes

,

Viva Questions

,

Important questions

,

Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

,

study material

,

MCQs

,

Exam

,

mock tests for examination

,

ppt

,

Summary

,

Previous year Questions (2016-20) - Chemical Bonding and Molecular Structure Notes | EduRev

;