Engineering Chemistry Questions and Answers Part-13

1. The main cause of molecular aggregation is ___________
a) Conduction
b) Induction
c) Inter-molecular interactions
d) Resonance

Answer: c
Explanation: The main cause of molecular aggregation is inter-molecular interactions. Inter-molecular interactions stem from the electric properties of atoms. Being the cause of molecular aggregation, inter-molecular forces are at the roots of chemistry and are the fabric of the world.

2. From where does the inter-molecular interaction originate?
a) From the electric properties of atoms
b) From the cohesive properties of atoms
c) From the magnetic properties of atoms
d) None of the mentioned

Answer: a
Explanation: Inter-molecular interactions originate from the electric properties of atoms. Inter-molecular interactions stem from the electric properties of atoms. Being the cause of molecular aggregation, inter-molecular forces are at the roots of chemistry and are the fabric of the world.

3. Which of the following is not a state of aggregation of matter?
a) Solid
b) Liquid and Gas
c) Plasma
d) None of the mentioned

Answer: d
Explanation: Solid, liquid, gas and plasma are the four states of aggregation of matter.

4. The process by which individual molecules form the defined aggregate is called ___________
a) Self-aggregation
b) Self-assembly
c) Aggregation
d) Assembly

Answer: b
Explanation: The process by which individual molecules form the defined aggregate is called self-assembly. Molecular self-assembly is the process by which molecules adopt a defined arrangement without guidance or management from an outside source.

5. In water, non-polar molecules tend to aggregate because they are forced to come into close proximity with each other due to ___________
a) Hydrophobic interactions
b) Hydrophilic interactions
c) Vander Waals interactions
d) Electrovalent interactions

Answer: a
Explanation: In water, non-polar molecules tend to aggregate because they are forced to come into close proximity with each other due to hydrophobic interactions.

6. Which type of molecules forms aggregate through a self-assembly process that is driven by the hydrophobic effect?
a) Electrophilic
b) Nucleophilic
c) Ambiphilic
d) None of the mentioned

Answer: c
Explanation: Ambiphilic molecules form aggregate through a self-assembly process that is driven by the hydrophobic effect. Molecular self-assembly is the process by which molecules adopt a defined arrangement without guidance or management from an outside source.

7. Why metallic bonds are non-directional?
a) Because there is a uniform distribution of mobile valence electrons around the kernels
b) Because there is a non-uniform distribution of mobile valence electrons around the kernels
c) There is no change in inter-kernel distance
d) There is a change in inter-kernel distance

Answer: a
Explanation: Metallic bonds are non-directional because there is a uniform distribution of mobile valence electrons around the kernels, provided there is no change in inter-kernel distance.

8. The number of molecules in a conduction band ___________
a) Increases with fall in temperature
b) Decreases with a rise in temperature
c) Increases with a rise in temperature
d) Does not depend upon the temperature

Answer: c
Explanation: The number of molecules in the conduction band increases with the rise in temperature. At high temperatures, randomness increases and more molecules move towards the conduction band.

9. What is the molecular formula of stearate ion?
a) C17H35COO
b) C35H17COO+
c) C35H17COO
d) C17H35COO+

Answer: a
Explanation: Sodium stearate ionises to form stearate anion(C17H35COO) and sodium cation(Na+).

10. Which part of the stearate ion is hydrophilic in nature?
a) Tail
b) Hydrocarbon chain
c) Head
d) None of the mentioned

Answer: c
Explanation: The end of the hydrocarbon chain is having a polar group (head) which is hydrophilic in nature and represented by a hollow circle.