Physical Chemistry Questions and Answers – Molecular Electronic Structure

This set of Physical Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Molecular Electronic Structure”.

1. What is responsible for the attraction of molecules in a crystal?
a) Hydrogen bond
b) Electrostatic attraction
c) Van der Waal’s attraction
d) Dipole-dipole attraction
View Answer

Answer: c
Explanation: Strong covalent bonds are responsible for holding together the molecules or atoms in any crystal. These bonds are so strong but still a weak force of attraction exists between them. And, this weak force of attraction is called Van der Waal’s forces.

2. Which of the following has a pyramidal shape?
a) SO3
b) NH3
c) CO32-
d) NO3
View Answer

Answer: b
Explanation: The molecule NH3 has sp3 hybridization. Also, NH3 has pyramidal shape because it is attached with three hydrogen atoms and also contains a lone pair of electron, which makes the shape of the molecule tetrahedral or pyramidal.

3. Why CN, NO+ have the same order of bond?
a) Both contain 13 electrons
b) Both contain 12 electrons
c) Both contain 15 electrons
d) Both contain 14 electrons
View Answer

Answer: d
Explanation: CN and NO+ both contain 14 electrons each. CN has total 14 electrons (6 from carbon, 7 from nitrogen plus 1 negative charge) and NO+ also has total 14 electrons (8 from oxygen, 7 from nitrogen and subtract 1 positive charge). Therefore, CN and NO+ have the same order of bond.

4. Why O2 is paramagnetic in nature?
a) Presence of paired electrons
b) Zero dipole moment
c) Presence of unpaired electron
d) Net dipole moment
View Answer

Answer: c
Explanation: Paramagnetic compounds consist of unpaired electrons and O2 contains one unpaired electron. Therefore, O2 is paramagnetic because of the presence of one unpaired electron. Therefore, it shows some paramagnetic properties too.

5. Why SF4 is a polar molecule?
a) It has lone pairs
b) It doesn’t have lone pairs
c) It has lone pairs but not around the central atom
d) Free radicals are present
View Answer

Answer: a
Explanation: If there are some lone pairs of electrons around the central atom and there is an odd number, then the molecule is considered as polar. SF4 is a polar molecule because it contains a lone pair with 4 electronegative atoms surrounding it.

6. Which of the following has the linear shape?
a) NO2+
b) SO2
c) O3
d) NO2
Answer: a
Explanation: NO2+ has a linear shape/structure because of the presence of sp hybridization in N+ ion in NO2+ molecule whereas NO2 has bent structure, SO2 has pyramidal structure and O3 has trigonal planar structure.

Sanfoundry Global Education & Learning Series – Physical Chemistry.


To practice all areas of Physical Chemistry, here is complete set of Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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