1. The energy which must be transferred to any atom to dislodge an electron is called?
a) Free energy
b) Ionization Energy
c) Quantum mechanical energy
d) Dissociation Energy
Answer
Answer: b [Reason:] If the energy is absorbed it is called endothermic and if the energy is released it is called exothermic energy.
2. Potassium Ion K+ has the same electronic configuration as that of which noble gases mentioned below ?
a) Krypton
b) Xenon
c) Argon
d) Radon
Answer
Answer: c [Reason:] Potassium has atomic number 19, hence it has 19 electrons and therefore K+ has 18 electrons, which is the same as noble gas Argon.
3. Ten covalent bonds in the Lewis structure of Propane will account for how many valence electrons?
a) 10
b) 20
c) 14
d) 12
Answer
Answer: b [Reason:] From the Molecular formula of Propane (C3H8), 3C has 3*4=12 valence electrons and 8H has 8*1=8 valence electrons and hence total valence electrons is given by their sum: 12+8=20.
4. What is the hybridization of oxygen in water?
a) sp
b) sp2
c) sp3
4) sp3d
Answer
Answer: c [Reason:] water has a linear shape as hydrogen shares its electron with p-orbital.
5. The electronegativity difference between the covalently bonded atoms is
a) Less than 0
b) 0-0.3
c) 0.3-1.7
d) Over 1.7
Answer
Answer: b [Reason:] The electronegativity difference between covalent bond atoms is 0-0.3, whereas for polar covalent bonded atoms it is between 0.3-1.7 and for ionic it is over 1.7.
6. What is the hybridization of Carbon atom in CF4?
a) sp2
b) sp
c) sp3d
d) sp3
Answer
Answer: d [Reason:] CF4 has a tetrahedral structure and carbon in it has a hybridization of sp3.
7. Which one has zero dipole moment?
a) C6H6
b) NH3
c) H2S
d) NO
Answer
Answer: a [Reason:] The ring of benzene is completely closed and is of perfect stability and hence it has zero dipole moment.
8. Which one have both sigma and pi bonds?
a) H2S
b) NO2
c) HClO
d) NaCN
Answer
Answer: d [Reason:] In NaCN both double bond and triple bond is present and hence it has both sigma
and pi bonds.
9. PH3, So3, and HF are examples of polar molecules. State true or false
a) True
b) False
Answer
Answer: b [Reason:] SO3 is not an example of polar molecule as it does not contain a hydrogen bond.
10. What is the hybridization of sulphur in H2S?
a) sp
b) sp2
c) sp3
d) sp3d
Answer
Answer: c [Reason:] S has two pairs of electrons and two atoms bonded to H with a total of 4 electrons and hence it has a hybridization of sp3.
