1. The energy which must be transferred to any atom to dislodge an electron is called?
- 1) Dissociation Energy
- 2) Quantum mechanical energy
- 3) Ionization Energy
- 4) Free energy
Answer: 3)
Explanation: 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 ?
- 1) Radon
- 2) Argon
- 3) Xenon
- 4) Krypton
Answer: 2)
Explanation: 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?
Answer: 3)
Explanation: 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?
- 1) sp3d
- 2) sp3
- 3) sp2
- 4) sp
Answer: 2)
Explanation: Water has a linear shape as hydrogen shares its electron with p-orbital.
5. The electronegativity difference between the covalently bonded atoms is
- 1) Over 1.7
- 2) 0.3-1.7
- 3) 0-0.3
- 4) Less than 0
Answer: 3)
Explanation: 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 CF<sub>4</sub>?
- 1) sp3
- 2) sp3d
- 3) sp
- 4) sp2
Answer: 1)
Explanation: CF₄ has a tetrahedral structure and carbon in it has a hybridization of sp3.
7. Which one has zero dipole moment?
- 1) H₂S
- 2) NO
- 3) NH₃
- 4) C₆H₆
Answer: 4)
Explanation: 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?
- 1) NaCN
- 2) HClO
- 3) NO₂
- 4) H₂S
Answer: 1)
Explanation: 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.
Answer: 1)
Explanation: 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?
- 1) sp3d
- 2) sp3
- 3) sp2
- 4) sp
Answer: 2)
Explanation: 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.
