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All questions of January Week 2 for NEET Exam
Which of the following is/are poikilotherm:?- a)Tapeworm and rabbits
- b)Elephants
- c)Humans and fishes
- d)Tapeworm and naked mole rat
Correct answer is option 'D'. Can you explain this answer?
Which of the following is/are poikilotherm:?
a)
Tapeworm and rabbits
b)
Elephants
c)
Humans and fishes
d)
Tapeworm and naked mole rat
|
Divey Sethi answered |
In the given scenario, the laboratory population of fruit flies consists of 40 fruit flies, and during a specified time interval, 4 individuals died. To calculate the death rate, we divide the number of deaths by the total population.
Number of deaths = 4
Total population = 40
Total population = 40
Death rate = Number of deaths / Total population
= 4 / 40
= 0.1 individuals per fruitfly per week
= 4 / 40
= 0.1 individuals per fruitfly per week
Option a) "0.1 individuals per fruitfly per week" is the correct answer because it accurately represents the death rate calculated based on the given information.
A statement 933 females per 1000 males depict:- a)ecological ages
- b)generation time
- c)sex ratio
- d)biotic potential
Correct answer is option 'C'. Can you explain this answer?
A statement 933 females per 1000 males depict:
a)
ecological ages
b)
generation time
c)
sex ratio
d)
biotic potential
|
Aman Sharma answered |
Sex ratio is the no of female available per thousands of male in a population. Sex ratio is decline due to female feticides alarmingly in some part of India.
Orchid shows commensalism as interaction with:- a)bee
- b)mango tree
- c)both mango tree and bee
- d)none of these
Correct answer is option 'B'. Can you explain this answer?
Orchid shows commensalism as interaction with:
a)
bee
b)
mango tree
c)
both mango tree and bee
d)
none of these
|
Shivani Rane answered |
Commensalism is interaction in which one species is benefited by other is neither benefited nor harmed. Orchids growing on mango tree do not harm the mango plants but get shelter.
If the Young’s apparatus is immersed in water, the effect on fringe width will- a)remain same
- b)decrease
- c)increase
- d)Cant say because the experiment cannot be carried in any other medium except air
Correct answer is option 'B'. Can you explain this answer?
If the Young’s apparatus is immersed in water, the effect on fringe width will
a)
remain same
b)
decrease
c)
increase
d)
Cant say because the experiment cannot be carried in any other medium except air
|
Kalyan Joshi answered |
Effect of Immersing Young's Apparatus in Water on Fringe Width
When the Young's apparatus is immersed in water, the effect on the fringe width can be explained as follows:
1. Refractive Index of Water: Water has a higher refractive index than air. This means that light passing through water will be bent more than in air.
2. Path Difference: Path difference is the difference in the distance traveled by two waves from the source to the point where they interfere with each other. When the apparatus is immersed in water, the path difference between the two waves will change due to the change in refractive index.
3. Decrease in Fringe Width: As the path difference changes, the interference pattern will also change. The fringe width will decrease because the change in the path difference will cause the interference pattern to become more spread out.
4. Explanation: The fringe width is inversely proportional to the square root of the refractive index. Since the refractive index of water is higher than air, the fringe width will decrease when the apparatus is immersed in water.
Conclusion
In conclusion, when the Young's apparatus is immersed in water, the fringe width will decrease due to the change in refractive index, which leads to a change in the path difference and the interference pattern.
When the Young's apparatus is immersed in water, the effect on the fringe width can be explained as follows:
1. Refractive Index of Water: Water has a higher refractive index than air. This means that light passing through water will be bent more than in air.
2. Path Difference: Path difference is the difference in the distance traveled by two waves from the source to the point where they interfere with each other. When the apparatus is immersed in water, the path difference between the two waves will change due to the change in refractive index.
3. Decrease in Fringe Width: As the path difference changes, the interference pattern will also change. The fringe width will decrease because the change in the path difference will cause the interference pattern to become more spread out.
4. Explanation: The fringe width is inversely proportional to the square root of the refractive index. Since the refractive index of water is higher than air, the fringe width will decrease when the apparatus is immersed in water.
Conclusion
In conclusion, when the Young's apparatus is immersed in water, the fringe width will decrease due to the change in refractive index, which leads to a change in the path difference and the interference pattern.
Two coherent sources produce a dark fringe when phase difference between the interfering waves is(n integer)- a)2π
- b)(2n – 1)π
- c)zero
- d)n
Correct answer is option 'B'. Can you explain this answer?
Two coherent sources produce a dark fringe when phase difference between the interfering waves is(n integer)
a)
2π
b)
(2n – 1)π
c)
zero
d)
n
|
Shruti Sarkar answered |
Dark fringes will be produced when there are destructive interference. The condition for that is the two waves should have a phase difference of an odd integral multiple of π.
The birth rate if 7 new plants are added to previous year plant population of 23 Salvinia plants will be:- a)0.3
- b)0.25
- c)0.4
- d)0.5
Correct answer is option 'A'. Can you explain this answer?
The birth rate if 7 new plants are added to previous year plant population of 23 Salvinia plants will be:
a)
0.3
b)
0.25
c)
0.4
d)
0.5
|
Rohan Unni answered |
The birth rate of a population = new individual added / previous population. Here birth rate= 7/23=0.3043. Hence, birth rate of Salvinia plants is equal to 0.3.
Interacting members of species live close to each other in following interaction/s:- a)parasitism
- b)competition
- c)commensalism, predation and parasitism
- d)commensalism
Correct answer is option 'C'. Can you explain this answer?
Interacting members of species live close to each other in following interaction/s:
a)
parasitism
b)
competition
c)
commensalism, predation and parasitism
d)
commensalism
|
Sushant Goyal answered |
Interacting members of species live close to each other in commensalism, predation and parasitism.
Young’s double slit experiment is carried out using two bulbs instead of using two slits and one source. Then- a)Fringes will be elliptical
- b)No interference fringes will be observed
- c)Fringes will be dark
- d)The interference fringes will be colored
Correct answer is option 'B'. Can you explain this answer?
Young’s double slit experiment is carried out using two bulbs instead of using two slits and one source. Then
a)
Fringes will be elliptical
b)
No interference fringes will be observed
c)
Fringes will be dark
d)
The interference fringes will be colored
|
Rajesh Gupta answered |
We observe interference pattern when the size of the slits are comparable to the wavelength of light. But here, the size of the bulb is bigger than wavelength of light.
Exponential growth pattern in a population results into:- a)Sigmoid curve
- b)U-shaped curve
- c)J-shaped curve
- d)None of these
Correct answer is option 'C'. Can you explain this answer?
Exponential growth pattern in a population results into:
a)
Sigmoid curve
b)
U-shaped curve
c)
J-shaped curve
d)
None of these
|
Shalini Saha answered |
Exponential growth pattern in population results into j-shaped curve. During exponential growth faster growth occurs and j-shaped curve is formed when time v/s growth is drawn.
Which of the following could result as a product in the aldol condensation reaction?- a)4-methyl-3-penten-2-on
- b)4-methyl-4-penten-2-one
- c)4-methyl-5-hexen-2-one
- d)3-methyl-4-hexen-2-one
Correct answer is option 'A'. Can you explain this answer?
Which of the following could result as a product in the aldol condensation reaction?
a)
4-methyl-3-penten-2-on
b)
4-methyl-4-penten-2-one
c)
4-methyl-5-hexen-2-one
d)
3-methyl-4-hexen-2-one
|
Maulik Verma answered |
It is an α, β-unsaturated ketone which can be formed in an aldol condensation followed by dehydration.
In Young’s double slit experiment, the distance between the two slits is halved and the distance of the screen from the slit is doubled. The fringe width will be- a)Will become four times
- b)Doubled
- c)Remain same
- d)Halved
Correct answer is option 'A'. Can you explain this answer?
In Young’s double slit experiment, the distance between the two slits is halved and the distance of the screen from the slit is doubled. The fringe width will be
a)
Will become four times
b)
Doubled
c)
Remain same
d)
Halved
|
Anaya Patel answered |
Fringe width β=λD/d
On d′=d/2, D′=2D
New fringe width β′= λD′/d′=4β
On d′=d/2, D′=2D
New fringe width β′= λD′/d′=4β
When viewed in white light, a soap bubble shows colours because of- a)Interference
- b)Scattering
- c)Dispersion
- d)Diffraction
Correct answer is option 'A'. Can you explain this answer?
When viewed in white light, a soap bubble shows colours because of
a)
Interference
b)
Scattering
c)
Dispersion
d)
Diffraction
|
Nayanika Datta answered |
Soap Bubble and Colors
Introduction:
When white light passes through a soap bubble, it undergoes a phenomenon known as dispersion, resulting in the appearance of various colors. This colorful phenomenon is due to interference of light waves and can be explained by the principles of interference and thin film interference.
Interference:
Interference is the interaction of two or more light waves, resulting in either constructive or destructive interference. Constructive interference occurs when the peaks and troughs of the waves align, leading to reinforcement and the formation of bright regions. Destructive interference occurs when the peaks and troughs of the waves cancel each other out, resulting in dark regions.
Thin Film Interference:
A soap bubble can be considered as a thin film of water sandwiched between two layers of air. When light waves hit the surface of the soap bubble, a portion of the light is reflected, and another portion enters the bubble. This incident light can also be seen as a combination of different wavelengths, or colors, of light.
Multiple Reflections and Interference:
As the light waves enter the soap bubble, they undergo multiple reflections from the inner and outer surfaces of the film. These reflections create a path difference between the different waves. If the path difference is an integer multiple of the wavelength of light, constructive interference occurs, resulting in bright colors. If the path difference is a half-integer multiple of the wavelength, destructive interference occurs, leading to dark regions.
Dispersion:
In addition to interference, dispersion also plays a role in the formation of colors in soap bubbles. Dispersion is the phenomenon where different colors of light have different wavelengths and therefore different speeds when passing through a medium. As the light waves enter the soap film, they are separated into their constituent colors due to their different wavelengths. This separation of colors is what gives rise to the vibrant and distinct colors observed in soap bubbles.
Conclusion:
In conclusion, soap bubbles show colors when viewed in white light due to the phenomenon of interference and dispersion. The interaction of light waves in the thin film of the bubble, combined with the separation of colors based on their wavelengths, leads to the formation of various colors. This colorful display is a result of the complex interplay between interference and dispersion.
Introduction:
When white light passes through a soap bubble, it undergoes a phenomenon known as dispersion, resulting in the appearance of various colors. This colorful phenomenon is due to interference of light waves and can be explained by the principles of interference and thin film interference.
Interference:
Interference is the interaction of two or more light waves, resulting in either constructive or destructive interference. Constructive interference occurs when the peaks and troughs of the waves align, leading to reinforcement and the formation of bright regions. Destructive interference occurs when the peaks and troughs of the waves cancel each other out, resulting in dark regions.
Thin Film Interference:
A soap bubble can be considered as a thin film of water sandwiched between two layers of air. When light waves hit the surface of the soap bubble, a portion of the light is reflected, and another portion enters the bubble. This incident light can also be seen as a combination of different wavelengths, or colors, of light.
Multiple Reflections and Interference:
As the light waves enter the soap bubble, they undergo multiple reflections from the inner and outer surfaces of the film. These reflections create a path difference between the different waves. If the path difference is an integer multiple of the wavelength of light, constructive interference occurs, resulting in bright colors. If the path difference is a half-integer multiple of the wavelength, destructive interference occurs, leading to dark regions.
Dispersion:
In addition to interference, dispersion also plays a role in the formation of colors in soap bubbles. Dispersion is the phenomenon where different colors of light have different wavelengths and therefore different speeds when passing through a medium. As the light waves enter the soap film, they are separated into their constituent colors due to their different wavelengths. This separation of colors is what gives rise to the vibrant and distinct colors observed in soap bubbles.
Conclusion:
In conclusion, soap bubbles show colors when viewed in white light due to the phenomenon of interference and dispersion. The interaction of light waves in the thin film of the bubble, combined with the separation of colors based on their wavelengths, leads to the formation of various colors. This colorful display is a result of the complex interplay between interference and dispersion.
In which of the following interaction/s one species is benefitted while other is harmed?- a)parasitism only
- b)competition only
- c)predation and parasitism
- d)competition and amensalism
Correct answer is option 'C'. Can you explain this answer?
In which of the following interaction/s one species is benefitted while other is harmed?
a)
parasitism only
b)
competition only
c)
predation and parasitism
d)
competition and amensalism
|
Nayanika Dasgupta answered |
In predation and parasitism one species is benefitted while other is harmed. Parasite obtain food from host by harming them.
For which of the following would you expect distribution range to be badly affected if average Global temperature keeps increasing:- a)Stenothermal species
- b)Euryhaline species
- c)Both Stenothermal species and Euryhaline species
- d)Eurythermal species
Correct answer is option 'A'. Can you explain this answer?
For which of the following would you expect distribution range to be badly affected if average Global temperature keeps increasing:
a)
Stenothermal species
b)
Euryhaline species
c)
Both Stenothermal species and Euryhaline species
d)
Eurythermal species
|
Diya Datta answered |
A majority of organisms are restricted to narrow range of temperature. Such organisms are called stenothermal species. The distribution range of these species will be adversely affected if average global temperature keeps increasing.
Ecology is the study of the relationships between living organisms and:- a)Abiotic and biotic components
- b)Biotic components only
- c)Abiotic components only
- d)Non-living components only
Correct answer is option 'A'. Can you explain this answer?
Ecology is the study of the relationships between living organisms and:
a)
Abiotic and biotic components
b)
Biotic components only
c)
Abiotic components only
d)
Non-living components only
|
Milan Unni answered |
Ecology is the branch of biology that studies the relationships between living organisms and their environment. It is concerned with understanding how organisms interact with both the biotic (living) and abiotic (non-living) components of their surroundings.
In the Young’s double slit experiment, the distance of p th dark fringe from the central maximum is:- a)
- b)
- c)
- d)
Correct answer is option 'B'. Can you explain this answer?
In the Young’s double slit experiment, the distance of p th dark fringe from the central maximum is:
a)
b)
c)
d)
|
Neha Sharma answered |
Position of the pth dark fringe is at a distance of
y=(2p−1) (λD/2d) from the centre
where
λ: Wavelength
D: Distance between slits
d: slit width
y=(2p−1) (λD/2d) from the centre
where
λ: Wavelength
D: Distance between slits
d: slit width
In an interference experiment monochromatic light is replaced by white light, we will see:- a)uniform darkness on the screen
- b)a few coloured bands and then uniform illumination
- c)equally spaced white and dark bands
- d)uniform illumination on the screen
Correct answer is option 'B'. Can you explain this answer?
In an interference experiment monochromatic light is replaced by white light, we will see:
a)
uniform darkness on the screen
b)
a few coloured bands and then uniform illumination
c)
equally spaced white and dark bands
d)
uniform illumination on the screen
|
|
Arun Khanna answered |
Therefore if monochromatic light in Young's interference experiment is replaced by white light, then the waves of each wavelength form their separate interference patterns. The resultant effect of all these patterns is obtained on the screen. i.e., the waves of all colours reach at mid point M in same phase we will see.a few coloured bands and then uniform illumination
A is optically active and C is one of the several aldol possible in the above reaction.Q. The product B is stereomeric. If a mixture containing all stereoisomers of B is treated with excess of LiAIH4 followed by the acidification will give how many different isomeric diols ?- a)2
- b)4
- c)6
- d)8
Correct answer is option 'D'. Can you explain this answer?
A is optically active and C is one of the several aldol possible in the above reaction.
Q.
The product B is stereomeric. If a mixture containing all stereoisomers of B is treated with excess of LiAIH4 followed by the acidification will give how many different isomeric diols ?
a)
2
b)
4
c)
6
d)
8
|
Niti Saha answered |
An age pyramid with a wide base and narrow top indicates a population that is:- a)Changing
- b)Stable
- c)Declining
- d)Growing rapidly
Correct answer is option 'D'. Can you explain this answer?
An age pyramid with a wide base and narrow top indicates a population that is:
a)
Changing
b)
Stable
c)
Declining
d)
Growing rapidly
|
|
Rajesh Gupta answered |
An age pyramid with a wide base and narrow top indicates a population that is growing rapidly.
In an age pyramid, the width of each age group represents the proportion or percentage of individuals in that specific age group. A wide base indicates a larger population of young individuals, while a narrow top indicates a smaller population of older individuals.
When the base of an age pyramid is wide and the subsequent age groups gradually decrease in width towards the top, it suggests that there is a higher proportion of young individuals compared to older individuals. This is indicative of a population that is growing rapidly because there is a high birth rate.
Which growth pattern occurs when resources become progressively limiting in a population?- a)Logistic growth
- b)Exponential growth
- c)Constant growth
- d)Declining growth
Correct answer is option 'A'. Can you explain this answer?
Which growth pattern occurs when resources become progressively limiting in a population?
a)
Logistic growth
b)
Exponential growth
c)
Constant growth
d)
Declining growth
|
|
Tarun Saha answered |
Logistic growth
Logistic growth is a growth pattern that occurs when resources become progressively limiting in a population. It is a more realistic model of population growth compared to exponential growth, which does not take into account the carrying capacity of an environment.
Understanding logistic growth
Logistic growth is characterized by an initial exponential increase in population size, followed by a slowing down of growth as resources become limited. This is because as a population grows, it will eventually reach a point where there are not enough resources (such as food, water, and shelter) to support further growth.
Factors affecting logistic growth
Several factors influence the occurrence of logistic growth in a population:
1. Carrying capacity: The carrying capacity is the maximum number of individuals that an environment can sustainably support. As a population reaches this limit, resources become increasingly scarce, causing growth to slow down.
2. Density-dependent factors: These are factors that have a greater impact on population growth as population density increases. Examples include competition for resources, predation, and disease. As population density increases due to exponential growth, these factors become more significant in limiting growth.
3. Birth and death rates: In a logistic growth model, birth rates initially exceed death rates, leading to exponential growth. However, as resources become limiting, birth rates start to decline, and death rates may increase due to increased competition and reduced access to resources.
Graphical representation
Logistic growth is often represented graphically using an S-shaped curve. In the initial phase, the curve rises steeply, representing exponential growth. As the population approaches the carrying capacity, the curve levels off and reaches a plateau, indicating the slowing down of growth. At the carrying capacity, the population stabilizes and remains relatively constant.
Significance of logistic growth
Understanding logistic growth is crucial in ecology and population biology. It helps us predict and manage populations, determine the impacts of resource availability on population dynamics, and assess the sustainability of ecosystems. By considering the carrying capacity and the factors that influence population growth, we can make more accurate predictions and develop effective conservation and management strategies.
Logistic growth is a growth pattern that occurs when resources become progressively limiting in a population. It is a more realistic model of population growth compared to exponential growth, which does not take into account the carrying capacity of an environment.
Understanding logistic growth
Logistic growth is characterized by an initial exponential increase in population size, followed by a slowing down of growth as resources become limited. This is because as a population grows, it will eventually reach a point where there are not enough resources (such as food, water, and shelter) to support further growth.
Factors affecting logistic growth
Several factors influence the occurrence of logistic growth in a population:
1. Carrying capacity: The carrying capacity is the maximum number of individuals that an environment can sustainably support. As a population reaches this limit, resources become increasingly scarce, causing growth to slow down.
2. Density-dependent factors: These are factors that have a greater impact on population growth as population density increases. Examples include competition for resources, predation, and disease. As population density increases due to exponential growth, these factors become more significant in limiting growth.
3. Birth and death rates: In a logistic growth model, birth rates initially exceed death rates, leading to exponential growth. However, as resources become limiting, birth rates start to decline, and death rates may increase due to increased competition and reduced access to resources.
Graphical representation
Logistic growth is often represented graphically using an S-shaped curve. In the initial phase, the curve rises steeply, representing exponential growth. As the population approaches the carrying capacity, the curve levels off and reaches a plateau, indicating the slowing down of growth. At the carrying capacity, the population stabilizes and remains relatively constant.
Significance of logistic growth
Understanding logistic growth is crucial in ecology and population biology. It helps us predict and manage populations, determine the impacts of resource availability on population dynamics, and assess the sustainability of ecosystems. By considering the carrying capacity and the factors that influence population growth, we can make more accurate predictions and develop effective conservation and management strategies.
Comprehension Type
Direction (Q. Nos. 20-22) This section contains a paragraph, describing theory, experiments, data, etc.
Three questions related to the paragraph have been given. Each question has only one correct answer among the four given options (a), (b), (c) and (d).
Passage
Aldol condensation is an important reaction in organic chemistry, particularly for the formation of carbon-carbon bonds. This reaction typically involves the enolate ion derived from an aldehyde or ketone reacting with another carbonyl compound to form a β-hydroxy aldehyde or β-hydroxy ketone. This product can undergo dehydration to form an α,β-unsaturated carbonyl compound. The reaction is usually catalyzed by a base, although acid-catalyzed versions are also known. The presence of at least one α-hydrogen in the reactant is crucial for the aldol condensation to occur. Acetaldehyde, for example, can undergo aldol condensation to yield 3-hydroxybutanal, which can then dehydrate to form crotonaldehyde.
Ques: In the aldol condensation reaction of acetaldehyde (CH₃CHO), the initial product formed before dehydration is:
- a)2-Hydroxybutanal
- b)Crotonaldehyde
- c)3-Hydroxybutanal
- d)Acetone
Correct answer is option 'C'. Can you explain this answer?
Comprehension Type
Direction (Q. Nos. 20-22) This section contains a paragraph, describing theory, experiments, data, etc.
Three questions related to the paragraph have been given. Each question has only one correct answer among the four given options (a), (b), (c) and (d).
Three questions related to the paragraph have been given. Each question has only one correct answer among the four given options (a), (b), (c) and (d).
Passage
Aldol condensation is an important reaction in organic chemistry, particularly for the formation of carbon-carbon bonds. This reaction typically involves the enolate ion derived from an aldehyde or ketone reacting with another carbonyl compound to form a β-hydroxy aldehyde or β-hydroxy ketone. This product can undergo dehydration to form an α,β-unsaturated carbonyl compound. The reaction is usually catalyzed by a base, although acid-catalyzed versions are also known. The presence of at least one α-hydrogen in the reactant is crucial for the aldol condensation to occur. Acetaldehyde, for example, can undergo aldol condensation to yield 3-hydroxybutanal, which can then dehydrate to form crotonaldehyde.
Ques: In the aldol condensation reaction of acetaldehyde (CH₃CHO), the initial product formed before dehydration is:
a)
2-Hydroxybutanal
b)
Crotonaldehyde
c)
3-Hydroxybutanal
d)
Acetone
|
Amar Choudhary answered |
Understanding Aldol Condensation
Aldol condensation is a significant reaction in organic chemistry that allows for the formation of carbon-carbon bonds. When acetaldehyde is involved, the process can be broken down into key steps.
Formation of Enolate Ion
- The reaction begins with the formation of an enolate ion from acetaldehyde, which has at least one α-hydrogen.
- This enolate ion acts as a nucleophile, attacking another molecule of acetaldehyde.
Initial Product Formation
- The nucleophilic attack leads to the formation of a β-hydroxy aldehyde.
- In the case of acetaldehyde, the product formed is specifically 3-hydroxybutanal.
- This product has a hydroxyl group (-OH) and a carbonyl group (C=O) in its structure.
Dehydration Step
- The β-hydroxy aldehyde (3-hydroxybutanal) can undergo dehydration, resulting in the formation of an α,β-unsaturated carbonyl compound, which is crotonaldehyde.
- However, the question specifically asks for the product formed before this dehydration occurs.
Conclusion
- Therefore, the correct answer to the question is option 'C' - 3-hydroxybutanal, which is the initial product prior to dehydration in the aldol condensation of acetaldehyde.
Aldol condensation is a significant reaction in organic chemistry that allows for the formation of carbon-carbon bonds. When acetaldehyde is involved, the process can be broken down into key steps.
Formation of Enolate Ion
- The reaction begins with the formation of an enolate ion from acetaldehyde, which has at least one α-hydrogen.
- This enolate ion acts as a nucleophile, attacking another molecule of acetaldehyde.
Initial Product Formation
- The nucleophilic attack leads to the formation of a β-hydroxy aldehyde.
- In the case of acetaldehyde, the product formed is specifically 3-hydroxybutanal.
- This product has a hydroxyl group (-OH) and a carbonyl group (C=O) in its structure.
Dehydration Step
- The β-hydroxy aldehyde (3-hydroxybutanal) can undergo dehydration, resulting in the formation of an α,β-unsaturated carbonyl compound, which is crotonaldehyde.
- However, the question specifically asks for the product formed before this dehydration occurs.
Conclusion
- Therefore, the correct answer to the question is option 'C' - 3-hydroxybutanal, which is the initial product prior to dehydration in the aldol condensation of acetaldehyde.
One Integer Value Correct TypeDirection (Q. Nos. 23-27) This section contains 5 questions. When worked out will result in an integer from 0 to 9 (both inclusive).Consider the following aldol condensation reaction,Butanone + NaOH (Dil.) → AldolsQ. How many different isomers (including stereoisomers) are formed above?
Correct answer is '6'. Can you explain this answer?
One Integer Value Correct Type
Direction (Q. Nos. 23-27) This section contains 5 questions. When worked out will result in an integer from 0 to 9 (both inclusive).
Consider the following aldol condensation reaction,
Butanone + NaOH (Dil.) → Aldols
Q.
How many different isomers (including stereoisomers) are formed above?
|
Tejas Desai answered |
In Young’s double slit experiment, one slit is covered. The observed effect will be- a)intensities of the fringes will be reduced
- b)interference will not take place
- c)colored fringes will be produced
- d)dark fringes will be replaced by bright ones
Correct answer is option 'B'. Can you explain this answer?
In Young’s double slit experiment, one slit is covered. The observed effect will be
a)
intensities of the fringes will be reduced
b)
interference will not take place
c)
colored fringes will be produced
d)
dark fringes will be replaced by bright ones
|
|
Divyansh Kulkarni answered |
Adult fiction, the term "In Young" is not a commonly used phrase or concept. It is possible that you may be referring to a specific book or series that uses this term in a unique way, but without further information, it is difficult to provide a more specific answer. Can you please provide more context or information about what you are referring to?
Statement I : When a mixture of ethanal and propanal is treated with aqueous Na2CO3, four aldol (excluding stereoisomers) are formed.
Statement II : In mixed aldol condensation, two self and two cross condensation products are always formed.- a)Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I
- b)Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I
- c)Statement I is correct but Statement II is incorrect
- d)Statement II is correct but Statement I is incorrect
Correct answer is option 'C'. Can you explain this answer?
Statement I : When a mixture of ethanal and propanal is treated with aqueous Na2CO3, four aldol (excluding stereoisomers) are formed.
Statement II : In mixed aldol condensation, two self and two cross condensation products are always formed.
Statement II : In mixed aldol condensation, two self and two cross condensation products are always formed.
a)
Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I
b)
Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I
c)
Statement I is correct but Statement II is incorrect
d)
Statement II is correct but Statement I is incorrect
|
Rishika Chauhan answered |
It would be true only if both carbonyls are capable of forming enolates, i.e. possesses α-H
Which type of interaction benefits both species involved?- a)Competition
- b)Predation
- c)Mutualism
- d)Parasitism
Correct answer is option 'C'. Can you explain this answer?
Which type of interaction benefits both species involved?
a)
Competition
b)
Predation
c)
Mutualism
d)
Parasitism
|
|
Rajesh Gupta answered |
Interactions between species can have different outcomes. In mutualism, both species benefit from the interaction. This means that there is a mutually beneficial relationship where both species gain advantages, such as access to food, protection, or reproductive assistance.
Option d) Mutualism is the correct answer because it accurately identifies the type of interaction where both species involved benefit from each other.
One or More than One Options Correct Type
Direction (Q. Nos. 11-15) This section contains 5 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONE or MORE THAN ONE are correct.
Q.
Successful mixed aldol condensation will be favoured
- a)treatment of electrophilic carbonyl component with stoichiometric strong base prior to the addition of the pre-nucleophilic carbonyl component
- b)treatment of mixture of electrophilic carbonyl component and pre-nucleophilic component with stoichiometric strong base
- c)continuous removal of aldol product from reaction mixture
- d)treatment of pre-nucleophilic carbonyl component with stoichiometric strong base prior to the addition of electrophilic carbonyl component.
Correct answer is option 'C,D'. Can you explain this answer?
One or More than One Options Correct Type
Direction (Q. Nos. 11-15) This section contains 5 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONE or MORE THAN ONE are correct.
Q.
Successful mixed aldol condensation will be favoured
a)
treatment of electrophilic carbonyl component with stoichiometric strong base prior to the addition of the pre-nucleophilic carbonyl component
b)
treatment of mixture of electrophilic carbonyl component and pre-nucleophilic component with stoichiometric strong base
c)
continuous removal of aldol product from reaction mixture
d)
treatment of pre-nucleophilic carbonyl component with stoichiometric strong base prior to the addition of electrophilic carbonyl component.
|
|
Rishika Chauhan answered |
For successful mixed aldol condensation to be favored, the correct conditions should ensure that one carbonyl component acts as a nucleophile while the other acts as an electrophile. Here's the analysis of each option:
(a) Treatment of electrophilic carbonyl component with a stoichiometric strong base before the addition of the pre-nucleophilic carbonyl component
- This would likely deprotonate the electrophilic carbonyl component, making it a poor electrophile and favoring side reactions. This is not favorable for a successful mixed aldol reaction.
(Incorrect)
(b) Treatment of mixture of electrophilic carbonyl component and pre-nucleophilic component with stoichiometric strong base
- This could result in deprotonation on both components, leading to a mixture of products and possibly side reactions.
(Incorrect)
(c) Continuous removal of aldol product from the reaction mixture
- Removing the aldol product shifts the equilibrium towards product formation, which is a beneficial condition for successful mixed aldol condensation.
(Correct)
(d) Treatment of pre-nucleophilic carbonyl component with stoichiometric strong base prior to the addition of electrophilic carbonyl component
- This ensures that the pre-nucleophilic component forms an enolate, which can then attack the electrophilic carbonyl component without side reactions, favoring a successful aldol condensation.
(Correct)
Final Answer:
(c) and (d) are correct choices.
Statement TypeDirection (Q. Nos. 16-19) This section is based on Statement I and Statement II. Select the correct answer from the codes given below.Q. Statement I : In aldol condensation, enoiates are nucleophilic and reversibly attack the carbonyl carbon of aldehyde or ketone in the aldoi condensation.Statement II : An aldoi on refluxing with dilute base gives back the carbonyl compound.- a)Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I
- b)Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I
- c)Statement I is correct but Statement II is incorrect
- d)Statement II is correct but Statement I is incorrect
Correct answer is option 'A'. Can you explain this answer?
Statement Type
Direction (Q. Nos. 16-19) This section is based on Statement I and Statement II. Select the correct answer from the codes given below.
Q.
Statement I : In aldol condensation, enoiates are nucleophilic and reversibly attack the carbonyl carbon of aldehyde or ketone in the aldoi condensation.
Statement II : An aldoi on refluxing with dilute base gives back the carbonyl compound.
a)
Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I
b)
Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I
c)
Statement I is correct but Statement II is incorrect
d)
Statement II is correct but Statement I is incorrect
|
Tarun Chakraborty answered |
Reversibility of aldol into carbonyls establishes that carbanion nucleophile is formed in first fast reversible step.
Which compound (s) below can react via an intramolecular aldol condensation to give a six membered ring?- a)
- b)
- c)
- d)
Correct answer is option 'A,C,D'. Can you explain this answer?
Which compound (s) below can react via an intramolecular aldol condensation to give a six membered ring?
a)
b)
c)
d)
|
Sinjini Tiwari answered |
All of these react in aldol reaction giving six-membered ring via intramolecular reaction.
Option (b) gives five and seven membered ring intramolecular aldol condensation.
Option (b) gives five and seven membered ring intramolecular aldol condensation.
Which of the following in conserved when light waves interfere?- a)Mass
- b)Amplitude
- c)Energy
- d)Intensity
Correct answer is option 'C'. Can you explain this answer?
Which of the following in conserved when light waves interfere?
a)
Mass
b)
Amplitude
c)
Energy
d)
Intensity
|
|
Rohan Singh answered |
A wave can transmit energy from one place to another.
The incorrect statement regarding aldol condensation is- a)It accomplishes the formation of a new C—C bond
- b)The enolate is favoured at equilibrium
- c)The key step in the mechanism of base catalysed reaction is attack of α-carbon of an enolate ion on the carbonyl carbo
- d)Dehydration of aldol gives α, β-unsaturated carbonyl compound
Correct answer is option 'B'. Can you explain this answer?
The incorrect statement regarding aldol condensation is
a)
It accomplishes the formation of a new C—C bond
b)
The enolate is favoured at equilibrium
c)
The key step in the mechanism of base catalysed reaction is attack of α-carbon of an enolate ion on the carbonyl carbo
d)
Dehydration of aldol gives α, β-unsaturated carbonyl compound
|
|
Niti Saha answered |
Enolate is formed in first fast step which undergo nucleophilic addition in second slow step.
Which of the following is/are true regarding aldol condensation ?- a)Both acid and base can act as catalyst
- b)A new carbon-carbon bond is always formed
- c)CH3CHO and D3C—CHO react at same rate if all other conditions are similar
- d)Prqpanal and propanone react at same rate if all other conditions are similar
Correct answer is option 'A,B,C'. Can you explain this answer?
Which of the following is/are true regarding aldol condensation ?
a)
Both acid and base can act as catalyst
b)
A new carbon-carbon bond is always formed
c)
CH3CHO and D3C—CHO react at same rate if all other conditions are similar
d)
Prqpanal and propanone react at same rate if all other conditions are similar
|
Aravind Mehra answered |
Both acid and base catalyses aldol reaction. In aldol reaction , a new α - β C—C bond is always formed . α - H is lost in first fast step, hence both CH3CHO and CD3CHO react at the same rate.
Consider the following modified aldol condensation,
Q. How many ethanal, at the most, will react with one molecule of nitromethane?
Correct answer is '3'. Can you explain this answer?
Consider the following modified aldol condensation,
Q.
How many ethanal, at the most, will react with one molecule of nitromethane?
|
Chirag Banerjee answered |
All three hydrogen can be deprotonated from nitromethane giving
In the following reaction,
Q. The major final product is- a)HO—CH2—CH2—CHO
- b)
- c)
- d)C(CH2OH)4
Correct answer is option 'C'. Can you explain this answer?
In the following reaction,
Q.
The major final product is
a)
HO—CH2—CH2—CHO
b)
c)
d)
C(CH2OH)4
|
Rajdeep Saini answered |
Repeated aidol condensation occur due to very high reactivity of formaldehyde towards nucleophile.
Statement I : In the reaction below,
A single aldol product is formed in 100% yield.Statement II : Cross aldol product is formed as major product.- a)Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I
- b)Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I
- c)Statement I is correct but Statement II is incorrect
- d)Statement II is correct but Statement I is incorrect
Correct answer is option 'D'. Can you explain this answer?
Statement I : In the reaction below,
A single aldol product is formed in 100% yield.
Statement II : Cross aldol product is formed as major product.
a)
Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I
b)
Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I
c)
Statement I is correct but Statement II is incorrect
d)
Statement II is correct but Statement I is incorrect
|
|
Rajdeep Saini answered |
Both self-aldol of cyclohexanone (although minor one) and cross aldol are formed.
Consider the following reaction,
Q. Which of the labeiled C—C bond formation is not possible in the above reaction? - a)only i
- b)only ii
- c)only iii
- d)only iv
Correct answer is option 'A'. Can you explain this answer?
Consider the following reaction,
Q.
Which of the labeiled C—C bond formation is not possible in the above reaction?
a)
only i
b)
only ii
c)
only iii
d)
only iv
|
|
Ashwin Iyer answered |
An α-βC—C bond is always formed in aidol reaction .
In a mixed aldoi condensation with ethanal as one aidehyde, which other from the following is expected to give maximum yield of cross condensation product?- a)
- b)
- c)
- d)
Correct answer is option 'C'. Can you explain this answer?
In a mixed aldoi condensation with ethanal as one aidehyde, which other from the following is expected to give maximum yield of cross condensation product?
a)
b)
c)
d)
|
Yash Kumar answered |
Nucleophilic addition at carbonyl carbon of cyclopropane releases angle strain.
Consider the following aldol condensation reaction,
Q. The nucleophile is- a)
- b)
- c)
- d)
Correct answer is option 'C'. Can you explain this answer?
Consider the following aldol condensation reaction,
Q.
The nucleophile is
a)
b)
c)
d)
|
Pritam Malik answered |
In acid catalysed aldo! condensation, enol acts as a nucleophile.
Statement I : When 
is treated with dilute base.
is formed.Statement II : In the given compound, γ-H is most acidic, forms the required enolate.- a)Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I
- b)Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I
- c)Statement I is correct but Statement II is incorrect
- d)Statement II is correct but Statement I is incorrect
Correct answer is option 'A'. Can you explain this answer?
Statement I : When is treated with dilute base.
is formed.
is treated with dilute base. is formed.Statement II : In the given compound, γ-H is most acidic, forms the required enolate.
a)
Both Statement I and Statement II are correct and Statement II is the correct explanation of Statement I
b)
Both Statement I and Statement II are correct but Statement II is not the correct explanation of Statement I
c)
Statement I is correct but Statement II is incorrect
d)
Statement II is correct but Statement I is incorrect
|
Arnab Chavan answered |
What is(are) true about the following aldoi reaction?
- a)The major aldol is
- b)If a pure enantiomer of starting compound is taken, the racemic mixture of major aldoi would be formed
- c)Excluding stereoisomers, a total of three different aldoi would be formed
- d)Major aldoi on dehydration would give
Correct answer is option 'A,C,D'. Can you explain this answer?
What is(are) true about the following aldoi reaction?
a)
The major aldol is
b)
If a pure enantiomer of starting compound is taken, the racemic mixture of major aldoi would be formed
c)
Excluding stereoisomers, a total of three different aldoi would be formed
d)
Major aldoi on dehydration would give
|
Harsh Mehta answered |
Also, the starting compound has three different types of α-H, three different aldols can be formed in principle. If a pure enantiomer of starting compound is taken, a pair of diastereomers of aldol would be formed.
Only One Option Correct Type Direction (Q. Nos. 6-15) This section contains 10 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE is correct.Q. Which is the major product in the following reaction?
- a)
- b)
- c)
- d)
Correct answer is option 'B'. Can you explain this answer?
Only One Option Correct Type
Direction (Q. Nos. 6-15) This section contains 10 multiple choice questions. Each question has four choices (a), (b), (c) and (d), out of which ONLY ONE is correct.
Q.
Which is the major product in the following reaction?
a)
b)
c)
d)
|
Ishani Patel answered |
Which principle states that the superior competitor eliminates the inferior one in competition?- a) Mutualism principle
- b)Predation principle
- c)Carrying capacity principle
- d)Competitive exclusion principle
Correct answer is option 'D'. Can you explain this answer?
Which principle states that the superior competitor eliminates the inferior one in competition?
a)
Mutualism principle
b)
Predation principle
c)
Carrying capacity principle
d)
Competitive exclusion principle
|
|
Rajesh Gupta answered |
The principle that states that the superior competitor eliminates the inferior one in competition is the Competitive Exclusion Principle. This principle suggests that when two species compete for the same limited resources in an ecological niche, the species that is better adapted or more efficient at utilizing those resources will eventually outcompete and eliminate the other species from that particular niche.
The correct answer is option a) Competitive exclusion principle. This principle highlights the competitive interactions between species and how competition can lead to the exclusion of one species by another in certain ecological niches.
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