1
MCQ (Single Correct Answer)

JEE Main 2019 (Online) 9th January Morning Slot

According to molecular orbital theory, which of the following is true with respect to Li2+ and Li2$$-$$ ?
A
$$Li_2^ + $$ is unstable and $$Li_2^ - $$ is stable
B
$$Li_2^ + $$ is stable and $$Li_2^ - $$ unstable
C
Both are stable
D
Both are unstable

Explanation

$$Li_2^ + $$  (5 electrons) = $${\sigma _{1{s^2}}}\,\,\sigma _{1{s^2}}^ * \,\,{\sigma _{2{s^1}}}$$

$$Li_2^ - $$  (7 electrons) = $${\sigma _{1{s^2}}}\,\,\sigma _{1{s^2}}^ * \,\,{\sigma _{2{s^2}}}$$ $$\,\sigma _{2{s^1}}^ * \,$$

$$ \therefore $$   Bond order of $$Li_2^ + $$ = $${{3 - 2} \over 2}$$ = 0.5

Bond order of $$Li_2^ - $$ = $${{4 - 3} \over 2}$$ = 0.5

As both $$Li_2^ + $$ and $$Li_2^ - $$ has non-zero bond order, so both are stable.
2
MCQ (Single Correct Answer)

JEE Main 2019 (Online) 9th January Evening Slot

In which of the following process, the bond order has increased and paramagnetic character has charged to diamagnetic ?
A
NO $$ \to $$ NO+
B
N2 $$ \to $$ N2+
C
O2 $$ \to $$ O2+
D
O2 $$ \to $$ O22$$-$$

Explanation

Molecular orbital configuration of NO (15 electrons) is

$${\sigma _{1{s^2}}}\,\sigma _{1{s^2}}^ * \,{\sigma _{2{s^2}}}\,\sigma _{2{s^2}}^ * \,{\sigma _{2p_z^2}}\,{\pi _{2p_x^2}}\, = \,{\pi _{2p_y^2}}\,\pi _{2p_x^1}^ * \, = \,\pi _{2p_y^o}^ * $$

$$\therefore\,\,\,\,$$ Nb = 10

Na = 5

$$\therefore\,\,\,\,$$ BO = $${1 \over 2}\left[ {10 - 5} \right]$$ = 2.5

And in NO one unpaired electron is present , so it is paramagnetic.

Similarly Molecular orbital configuration of NO+ (14 electrons) is

$${\sigma _{1{s^2}}}\,\sigma _{1{s^2}}^ * \,{\sigma _{2{s^2}}}\,\sigma _{2{s^2}}^ * \,{\sigma _{2p_z^2}}\,{\pi _{2p_x^2}}\, = \,{\pi _{2p_y^2}}\,$$

$$\therefore\,\,\,\,$$ Nb = 10

Na = 4

$$\therefore\,\,\,\,$$ BO = $${1 \over 2}\left[ {10 - 4} \right]$$ = 3

And in NO+ no unpaired electron is present , so it is diamagnetic.
3
MCQ (Single Correct Answer)

JEE Main 2019 (Online) 10th January Morning Slot

Two pi and half sigma bonds are present in :
A
O2
B
N$$_2^ + $$
C
O$$_2^ + $$
D
N2

Explanation

Two pi and half sigma bonds are presents in molecule with bond order 2.5.

Moleculer orbital configuration of $$N_2^+$$ (13 electrons)

= $${\sigma _{1{s^2}}}\,\sigma _{1{s^2}}^ * \,{\sigma _{2{s^2}}}\,\sigma _{2{s^2}}^ * \,{\pi _{2p_x^2}}\, = \,{\pi _{2p_y^2}}\,{\sigma _{2p_z^1}}$$

Bond order = $${1 \over 2}\left( {9 - 4} \right)$$ = 2.5
4
MCQ (Single Correct Answer)

JEE Main 2019 (Online) 10th January Morning Slot

The type of hybridisation and number of lone pair (s) of electrons of Xe in XeOF4, respectively, are:
A
sp3d and 2
B
sp3d2 and 2
C
sp3d and 1
D
sp3d2 and 1

Explanation

H = $${1 \over 2}$$ (V + M - c + a)

$$ \therefore $$ H = $${1 \over 2}$$(8 + 4) = 6


From structure, it is clear that it has five bond pairs and one lone pair.

Questions Asked from Chemical Bonding & Molecular Structure

On those following papers in MCQ (Single Correct Answer)
Number in Brackets after Paper Name Indicates No of Questions
AIEEE 2002 (5)
keyboard_arrow_right
AIEEE 2003 (4)
keyboard_arrow_right
AIEEE 2004 (5)
keyboard_arrow_right
AIEEE 2005 (1)
keyboard_arrow_right
AIEEE 2006 (3)
keyboard_arrow_right
AIEEE 2007 (4)
keyboard_arrow_right
AIEEE 2008 (2)
keyboard_arrow_right
AIEEE 2009 (1)
keyboard_arrow_right
AIEEE 2011 (3)
keyboard_arrow_right
AIEEE 2012 (2)
keyboard_arrow_right
JEE Main 2013 (Offline) (2)
keyboard_arrow_right
JEE Main 2015 (Offline) (1)
keyboard_arrow_right
JEE Main 2016 (Online) 9th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2016 (Online) 10th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2017 (Offline) (1)
keyboard_arrow_right
JEE Main 2017 (Online) 8th April Morning Slot (2)
keyboard_arrow_right
JEE Main 2017 (Online) 9th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2018 (Offline) (3)
keyboard_arrow_right
JEE Main 2018 (Online) 15th April Morning Slot (4)
keyboard_arrow_right
JEE Main 2018 (Online) 15th April Evening Slot (2)
keyboard_arrow_right
JEE Main 2018 (Online) 16th April Morning Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 9th January Morning Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 9th January Evening Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 10th January Morning Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 10th January Evening Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 12th January Evening Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 8th April Evening Slot (4)
keyboard_arrow_right
JEE Main 2019 (Online) 9th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2019 (Online) 9th April Evening Slot (4)
keyboard_arrow_right
JEE Main 2019 (Online) 10th April Morning Slot (2)
keyboard_arrow_right
JEE Main 2019 (Online) 12th April Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 7th January Morning Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 7th January Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 8th January Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 8th January Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 9th January Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 9th January Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 2nd September Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 2nd September Evening Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 3rd September Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 3rd September Evening Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 4th September Morning Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 4th September Evening Slot (1)
keyboard_arrow_right
JEE Main 2020 (Online) 5th September Morning Slot (2)
keyboard_arrow_right
JEE Main 2020 (Online) 5th September Evening Slot (1)
keyboard_arrow_right
JEE Main 2021 (Online) 24th February Morning Slot (1)
keyboard_arrow_right
JEE Main 2021 (Online) 24th February Evening Slot (2)
keyboard_arrow_right
JEE Main 2021 (Online) 25th February Morning Slot (1)
keyboard_arrow_right
JEE Main 2021 (Online) 25th February Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 26th February Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 26th February Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 16th March Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 17th March Morning Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 17th March Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 18th March Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 20th July Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 22th July Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 25th July Evening Shift (2)
keyboard_arrow_right
JEE Main 2021 (Online) 26th August Evening Shift (1)
keyboard_arrow_right
JEE Main 2021 (Online) 27th August Morning Shift (2)
keyboard_arrow_right

EXAM MAP

Joint Entrance Examination

JEE Advanced JEE Main

Graduate Aptitude Test in Engineering

GATE CE GATE ECE GATE ME GATE IN GATE EE GATE CSE GATE PI

Medical

NEET