Welcome to the Conjugated Molecules MDCAT MCQs with Answers. In this post, we have shared Conjugated Molecules Multiple Choice Questions and Answers for PMC MDCAT 2024. Each question in MDCAT Biology offers a chance to enhance your knowledge regarding Conjugated Molecules MCQs in this MDCAT Online Test.
What characterizes conjugated molecules?
a) Presence of a single bond
b) Alternating single and double bonds
c) Presence of a metal ion
d) High molecular weight
Which of the following is a common example of a conjugated system?
a) Ethylene
b) Benzene
c) Methane
d) Acetylene
What is the main feature of conjugated pi systems that affects their electronic properties?
a) Delocalization of electrons
b) Presence of alkyl groups
c) Ionic bonding
d) Formation of hydrogen bonds
Which conjugated molecule is responsible for the color in carrots?
a) Lutein
b) Lycopene
c) Chlorophyll
d) Beta-carotene
In which type of conjugated system do electrons move freely across multiple bonds?
a) Aromatic systems
b) Aliphatic systems
c) Saturated systems
d) Non-conjugated systems
Which property of conjugated molecules contributes to their ability to absorb visible light?
a) High polarity
b) Delocalized π-electrons
c) Ionic bonds
d) Hydrogen bonding
What kind of light absorption is typically observed in conjugated systems?
a) Ultraviolet light only
b) Infrared light only
c) Visible light
d) X-rays
Which of the following is an example of a conjugated diene?
a) 1,3-Butadiene
b) Ethylene
c) Cyclohexane
d) Benzene
What is the term for the phenomenon where conjugated systems absorb light and produce color?
a) Resonance
b) Fluorescence
c) Chromophore
d) Chemiluminescence
Which property of conjugated systems is enhanced by increasing the number of conjugated double bonds?
a) Boiling point
b) Solubility in water
c) Absorption wavelength
d) Melting point
Which of the following compounds is an example of a conjugated ketone?
a) Acetone
b) Butanone
c) Benzophenone
d) Cyclohexanone
What structural feature is common in compounds like carotenoids?
a) Conjugated double bonds
b) Aromatic rings
c) Aliphatic chains
d) Ester groups
Which conjugated system is commonly used in organic light-emitting diodes (OLEDs)?
a) Anthracene
b) Cyclohexane
c) Ethylene
d) Cyclopropane
What kind of transition is responsible for the color of conjugated molecules?
a) π to π* transition
b) σ to σ* transition
c) n to π* transition
d) π to σ* transition
Which of the following compounds is an example of a conjugated polymer?
a) Polystyrene
b) Polyethylene
c) Polyacetylene
d) Polymethylmethacrylate
Which of the following contributes to the stability of conjugated systems?
a) Inductive effects
b) Hyperconjugation
c) Resonance effects
d) Electronegativity
In a conjugated system, what is the effect of extending the conjugation length on the electronic absorption spectrum?
a) Blue shift
b) Red shift
c) No change
d) Green shift
Which molecule has the longest conjugated system among the following?
a) Butadiene
b) Benzene
c) 1,3-Butadiene
d) Polycyclic aromatic hydrocarbons
Which characteristic is typical of conjugated systems in terms of their chemical reactivity?
a) High reactivity
b) Low reactivity
c) Non-reactive
d) Reactive only in acidic conditions
Which of the following structures is not considered conjugated?
a) 1,3-Butadiene
b) Benzene
c) Cyclohexane
d) Polyenes
What type of conjugated system is characterized by alternating double and single bonds across a ring structure?
a) Isolated double bonds
b) Conjugated diene
c) Aromatic ring
d) Non-conjugated polyene
Which conjugated molecule is used as a dye in UV-visible spectroscopy?
a) Methyl orange
b) Benzene
c) Cyclohexane
d) Methane
What effect does the presence of conjugated systems have on the absorption of UV light?
a) Decreases absorption
b) Increases absorption
c) No effect on absorption
d) Shifts absorption to higher wavelengths
Which of the following compounds would be least likely to show a strong UV absorption due to its conjugation?
a) Benzene
b) Cyclohexane
c) 1,3-Butadiene
d) Polyacetylene
What role do conjugated systems play in the color of plant pigments?
a) They increase absorption of visible light
b) They decrease absorption of visible light
c) They reflect visible light
d) They emit light
Which of the following features is not associated with conjugated systems?
a) Alternating single and double bonds
b) Enhanced color due to light absorption
c) Formation of hydrogen bonds
d) Electron delocalization
Which conjugated molecule is commonly used in organic solar cells?
a) Polythiophene
b) Benzene
c) Ethylene
d) Cyclohexane
What type of electronic transition is observed in conjugated systems during UV-visible spectroscopy?
a) π to π* transition
b) σ to σ* transition
c) n to π* transition
d) π to σ* transition
Which property of conjugated molecules allows them to act as light-absorbing agents in dyes and pigments?
a) The length of the conjugated system
b) The type of solvent used
c) The molecular weight
d) The presence of metal ions
Which of the following compounds is an example of a conjugated triene?
a) 1,3,5-Hexatriene
b) 1,2-Diene
c) Benzene
d) 1,3-Butadiene
Which of the following is a characteristic of conjugated systems in organic semiconductors?
a) High electrical conductivity
b) High thermal conductivity
c) Low solubility in organic solvents
d) Low optical absorption
What is the effect of conjugation on the melting point of organic compounds?
a) Increases the melting point
b) Decreases the melting point
c) No effect on melting point
d) Melting point becomes unstable
Which conjugated molecule is used in the production of red color in tomatoes?
a) Carotene
b) Lycopene
c) Chlorophyll
d) Beta-carotene
What is the impact of conjugation on the electronic transitions in conjugated polymers?
a) Broader absorption spectra
b) Narrower absorption spectra
c) No impact on absorption spectra
d) Changes the electronic configuration
Which of the following statements is true about conjugated molecules?
a) They always have a high molecular weight
b) They are highly reactive towards nucleophiles
c) They exhibit color due to their ability to absorb light
d) They do not exhibit any color
Which of the following is not typically a feature of conjugated systems?
a) Alternating double bonds
b) Electron delocalization
c) High solubility in non-polar solvents
d) Lack of color
What effect does conjugation have on the reactivity of organic molecules?
a) Increases reactivity
b) Decreases reactivity
c) No effect on reactivity
d) Makes molecules inert
Which of the following conjugated systems is known for its high stability and color absorption properties?
a) Benzene
b) Cyclohexane
c) Ethylene
d) 1,3-Butadiene
What does the term “conjugation” refer to in organic chemistry?
a) The presence of alternating single and double bonds
b) The presence of aromatic rings
c) The formation of hydrogen bonds
d) The ionic bonding between atoms
Which of the following is a property of conjugated organic molecules?
a) Increased melting point
b) Decreased solubility in organic solvents
c) Enhanced color due to light absorption
d) Low reactivity
In a conjugated system, which type of bond alternates with single bonds to create delocalization?
a) Triple bonds
b) Double bonds
c) Single bonds
d) Ionic bonds
Which conjugated molecule is known for its use as a fluorescent dye in biological research?
a) Rhodamine
b) Cyclohexane
c) Benzene
d) Methane
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