Laws of Photochemistry and Mesomeric Effect MCQs

By: Prof. Dr. Fazal Rehman | Last updated: November 27, 2024

1. When the molecule absorbs a photon, it is necessary that just one molecule react.
(A). False
(B). True
(E). None of these

Multiple Choice Question Answer: a

2. Stark-Einstein studied which of the following aspects of photochemical reactions by application of the quantum theory of light?
(A). Qualitative
(B). Geometrical
(C). Quantitative
(D). Qualitative and Quantitative
(E). None of these

Multiple Choice Question Answer: c

3. When a beam of light is allowed to pass through a transparent medium, which of the following is the rate of decrease of intensity with the thickness of medium to the intensity of the light?
(A). Inversely proportional
(B). Equal
(C). Directly proportional
(D). Not related
(E). None of these

Multiple Choice Question Answer: c

4. A resonance effect is ______
(A). Mesomeric effect
(B). Electromeric effect
(C). Inductive effect
(D). Inductomeric effect
(E). None of these

Multiple Choice Question Answer: a

5. What does the Phenyl group show?
(A). (-M) effect
(B). (+E) effect
(C). (+I) effect
(D). (+M) effect
(E). None of these

Multiple Choice Question Answer: a

6. Greater the number of resonating structures for a given intermediate ______ will be its stability.
(A). Less
(B). It will not affect
(C). More
(D). None of these
(E). None of these

Multiple Choice Question Answer: c

7. When the Beer-Lambert law is applicable?
(A). If temperature changes
(B). If the temperature varies linearly
(C). If non-monochromatic radiation is used
(D). If the dilute solution is used
(E). None of these

Multiple Choice Question Answer: d

8. In the mesomeric effect, the electrons are transferred from which of the following?
(A). A multiple bonds to an atom
(B). All of these
(C). An atom with a lone pair to the adjacent single covalent bond
(D). A multiple bonds to a single covalent bond
(E). None of these

Multiple Choice Question Answer: b

9. When light falls on a cell containing which of the following reaction mixture, component of light is responsible to produce the chemical reaction.
(A). Transmitted
(B). Adsorbed
(C). Absorbed
(D). Reflected
(E). None of these

Multiple Choice Question Answer: c

10. Which of the following is the correct statement?
(A). All the bond lengths in a benzene ring are always equal because of the resonance
(B). All the bond lengths in the benzene ring are always equal because of the hyperconjugation
(C). The Benzene ring has always two different types of bond lengths for a single and the double bonds
(D). All of these
(E). None of these

Multiple Choice Question Answer: a

11. The absorbed radiation never becomes the cause of the chemical reaction.
(A). False
(B). True
(E). None of these

Multiple Choice Question Answer: b

12. Which of the following is also known as the Principle of Photochemical Activation?
(A). Stark law
(B). Lambert’s law
(C). Draper law
(D). Grothus–Draper law
(E). None of these

Multiple Choice Question Answer: d

13. Which of the following is the phenomenon in which two or more structures, that involve the identical position of atoms, can be written for a particular molecule?
(A). Conjugation
(B). Hyper conjugation
(C). Resonance
(D). Vibration
(E). None of these

Multiple Choice Question Answer: c

14. The resonance energy is defined as a difference in energy between which of the following?
(A). Two consecutive resonating structures
(B). Resonance hybrid and most stable resonating structure
(C). Resonance hybrid and most unstable resonating structure
(D). First and last resonating structures
(E). None of these

Multiple Choice Question Answer: b

15. Which of the following is the incorrect option?
(A). None of these
(B). Actual structure always lies in between the various possible resonating structures
(C). The Resonating structures are very much useful as they allow us to describe the molecules
(D). Resonating structures have a real existence
(E). None of these

Multiple Choice Question Answer: d

16. The Dipole moment of CH3-CH2-Cl > CH2=CH-Cl.
(A). False
(B). True
(E). None of these

Multiple Choice Question Answer: b

17. The application of the mesomeric effect is ___________
(A). Dipole moment
(B). Strength of acids and bases
(C). All of these
(D). Bond length
(E). None of these

Multiple Choice Question Answer: c

18. What is the Grothus–Draper law in nature?
(A). Quantitative
(B). Purely qualitative
(C). Qualitative and Quantitative
(D). Non-acceptable
(E). None of these

Multiple Choice Question Answer: b

19. Which of the following is also known as the Principle of Quantum Activation?
(A). Lambert’s law
(B). Stark-Einstein law
(C). Beer’s law
(D). Stark law
(E). None of these

Multiple Choice Question Answer: b

20. What happens to the intensity of a beam of monochromatic light with the increase in the concentration of the absorbing substance arithmetically?
(A). Increase linearly
(B). Increase exponentially
(C). Decrease linearly
(D). Decrease exponentially
(E). None of these

Multiple Choice Question Answer: d

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