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All questions of Some basic principles of organic chemistry for NEET Exam
Which among the following defines Meso forms of isomers?
- a)Meso form is optically inactive due to external compensation.
- b)The molecules of the meso isomers are chiral.
- c)It can be separated into optically active enantiomeric pairs.
- d)It is a single compound.
Correct answer is option 'D'. Can you explain this answer?
Which among the following defines Meso forms of isomers?
a)
Meso form is optically inactive due to external compensation.
b)
The molecules of the meso isomers are chiral.
c)
It can be separated into optically active enantiomeric pairs.
d)
It is a single compound.
|
Rohan Singh answered |
Meso forms of isomers are single compounds and their molecules are achiral hence they cannot be separated into pairs.
Additional Information: A meso compound or meso isomer is a non-optically active member of a set of stereoisomers, at least two of which are optically active. This means that despite containing two or more stereogenic centers, the molecule is not chiral.
- a)3
- b)4
- c)5
- d)6
Correct answer is option 'D'. Can you explain this answer?
a)
3
b)
4
c)
5
d)
6
|
Krishna Iyer answered |
General formula of ketone = CnH2nO
12x+2x+16 = 100
x = 6
So, the formula of compound is C6H12O. We have to make ketone only. These are as follow
12x+2x+16 = 100
x = 6
So, the formula of compound is C6H12O. We have to make ketone only. These are as follow
- a)3
- b)4
- c)5
- d)7
Correct answer is option 'A'. Can you explain this answer?
a)
3
b)
4
c)
5
d)
7
|
|
Riya Banerjee answered |
The compounds with each doubly bonded carbon attached to two different groups (like Cab=Cab, Cab=Ccd) exhibit geometrical isomerism i.e., cis and trans forms. The geometrical isomerism arises due to restricted rotation of double bond.
However, even though there is restricted rotation for triple bond, alkynes do not exhibit geometrical isomerism, since the triply bonded carbons are attached to one group each only.
The observed order of the stability of the cabocation is:- a)(CH3)2CH+ < (CH3)3C+ 3+ < CH3CH2+
- b)CH3+ < CH3CH2+ <(CH3)2CH+ < (CH3)3C+
- c)CH3CH2+ <(CH3)2CH+ < (CH3)3C+ < CH3+
- d)CH3+ < CH3CH2+ < (CH3)3C+ <(CH3)2CH+
Correct answer is option 'B'. Can you explain this answer?
The observed order of the stability of the cabocation is:
a)
(CH3)2CH+ < (CH3)3C+ 3+ < CH3CH2+
b)
CH3+ < CH3CH2+ <(CH3)2CH+ < (CH3)3C+
c)
CH3CH2+ <(CH3)2CH+ < (CH3)3C+ < CH3+
d)
CH3+ < CH3CH2+ < (CH3)3C+ <(CH3)2CH+
|
|
Rajesh Gupta answered |
Alkyl groups directly attached to the +vely charged carbon stabilize the carbocations due to inductive and hyperconjugation effects.
Inductive effect:
→ Stability of carbocation
→ More number of +I group more stable carbocation.
Hyperconjugation:
Inductive effect:
→ Stability of carbocation
→ More number of +I group more stable carbocation.
Hyperconjugation:
Stability
∝Number of canonical structures
∝Number of H (alpha hydrogen)
∝Number of canonical structures
∝Number of H (alpha hydrogen)
Which is true about conformers of 1,1,2,2-tetrachloroethane?Which is true about conformers of 1,1,2,2-tetrachloroethane?
a) The most stable conformer has dihedral angle of 60° between all adjacent chlorine atoms
b) In the least stable conformer, two Cl-atoms are eclipsing one another while other two Cl-atoms are eclipsed to hydrogen atoms
c) In the most stable conformer, dihedral angle between hydrogen atoms is 60°
d) The most stable conformer is non-polar - a)The most stable conformer has dihedral angle of 60° between all adjacent chlorine atoms
- b)In the least stable conformer, two Cl-atoms are eclipsing one another while other two Cl-atoms are eclipsed to hydrogen atoms
- c)In the most stable conformer, dihedral angle between hydrogen atoms is 60°
- d)The most stable conformer is non-polar
Correct answer is option 'D'. Can you explain this answer?
Which is true about conformers of 1,1,2,2-tetrachloroethane?
Which is true about conformers of 1,1,2,2-tetrachloroethane?
a) The most stable conformer has dihedral angle of 60° between all adjacent chlorine atoms
b) In the least stable conformer, two Cl-atoms are eclipsing one another while other two Cl-atoms are eclipsed to hydrogen atoms
c) In the most stable conformer, dihedral angle between hydrogen atoms is 60°
d) The most stable conformer is non-polar
a) The most stable conformer has dihedral angle of 60° between all adjacent chlorine atoms
b) In the least stable conformer, two Cl-atoms are eclipsing one another while other two Cl-atoms are eclipsed to hydrogen atoms
c) In the most stable conformer, dihedral angle between hydrogen atoms is 60°
d) The most stable conformer is non-polar
a)
The most stable conformer has dihedral angle of 60° between all adjacent chlorine atoms
b)
In the least stable conformer, two Cl-atoms are eclipsing one another while other two Cl-atoms are eclipsed to hydrogen atoms
c)
In the most stable conformer, dihedral angle between hydrogen atoms is 60°
d)
The most stable conformer is non-polar
|
Mira Joshi answered |
The correct answer is option D
This molecule is non-polar two Cl atoms in one carbon atom cancel the polarity other two Cl atoms on the next carbon.
Also all the Cl atoms are at max distance from each other so max. Stability due to less repulsion between Cl atoms. Dihedral angle between H and Cl is 60°
This molecule is non-polar two Cl atoms in one carbon atom cancel the polarity other two Cl atoms on the next carbon.
Also all the Cl atoms are at max distance from each other so max. Stability due to less repulsion between Cl atoms. Dihedral angle between H and Cl is 60°
- a)3
- b)5
- c)7
- d)8
Correct answer is option 'C'. Can you explain this answer?
a)
3
b)
5
c)
7
d)
8
|
Neha Joshi answered |
The correct answer is Option B.
5 isomers are possible. C5H10(CnH2n). Molecules having the CnH2n formulas are most likely to be cyclic alkanes. The five isomers are:
(1) Cyclopentane
(2) 1-Methylcyclobutane
(3) 1-Ethylcyclopropane
(4) 1,1-Dimethylcyclopropane
(5) 1,2-Dimethylcyclopropane
5 isomers are possible. C5H10(CnH2n). Molecules having the CnH2n formulas are most likely to be cyclic alkanes. The five isomers are:
(1) Cyclopentane
(2) 1-Methylcyclobutane
(3) 1-Ethylcyclopropane
(4) 1,1-Dimethylcyclopropane
(5) 1,2-Dimethylcyclopropane
[JEE Main 2014 Online Exam]- a)a
- b)b
- c)c
- d)d
Correct answer is option 'B'. Can you explain this answer?
[JEE Main 2014 Online Exam]
a)
a
b)
b
c)
c
d)
d
|
Siddharth Mehra answered |
The correct answer is option 'B' - sp2 and sp.
Explanation:
In allene (C3H4), there are two carbon atoms, each with three sigma bonds. To determine the hybridization of the carbon atoms, we need to look at their bonding and lone pairs of electrons.
1. Hybridization of the first carbon atom:
- The first carbon atom is bonded to two other carbon atoms and one hydrogen atom.
- It has three sigma bonds, which means it will have three hybrid orbitals.
- The carbon atom also has one lone pair of electrons.
- The presence of three sigma bonds and one lone pair indicates sp2 hybridization.
- Therefore, the first carbon atom is sp2 hybridized.
2. Hybridization of the second carbon atom:
- The second carbon atom is also bonded to two other carbon atoms and one hydrogen atom.
- It also has three sigma bonds, which means it will have three hybrid orbitals.
- The carbon atom does not have any lone pairs of electrons.
- The presence of only three sigma bonds indicates sp hybridization.
- Therefore, the second carbon atom is sp hybridized.
In summary, in allene (C3H4), the type of hybridization of the carbon atoms is sp2 and sp.
Explanation:
In allene (C3H4), there are two carbon atoms, each with three sigma bonds. To determine the hybridization of the carbon atoms, we need to look at their bonding and lone pairs of electrons.
1. Hybridization of the first carbon atom:
- The first carbon atom is bonded to two other carbon atoms and one hydrogen atom.
- It has three sigma bonds, which means it will have three hybrid orbitals.
- The carbon atom also has one lone pair of electrons.
- The presence of three sigma bonds and one lone pair indicates sp2 hybridization.
- Therefore, the first carbon atom is sp2 hybridized.
2. Hybridization of the second carbon atom:
- The second carbon atom is also bonded to two other carbon atoms and one hydrogen atom.
- It also has three sigma bonds, which means it will have three hybrid orbitals.
- The carbon atom does not have any lone pairs of electrons.
- The presence of only three sigma bonds indicates sp hybridization.
- Therefore, the second carbon atom is sp hybridized.
In summary, in allene (C3H4), the type of hybridization of the carbon atoms is sp2 and sp.
Consider all possible isomeric ketones, including stereoisomers of Molecular weight 100. All these isomers are independently reacted with NaBH4
(Note stereoisomers are also reacted separately). The total number of ketones that give a racemic product(s) is/are
[JEE Advanced 2014] - a)3
- b)4
- c)5
- d)6
Correct answer is option 'C'. Can you explain this answer?
Consider all possible isomeric ketones, including stereoisomers of Molecular weight 100. All these isomers are independently reacted with NaBH4
(Note stereoisomers are also reacted separately). The total number of ketones that give a racemic product(s) is/are
(Note stereoisomers are also reacted separately). The total number of ketones that give a racemic product(s) is/are
[JEE Advanced 2014]
a)
3
b)
4
c)
5
d)
6
|
Pooja Shah answered |
The general formula of isomeric ketone having molecular mass 100 is C6H12O [6×12+12×1+16].
The possible structure will be :
The number of ketones that gives racemic mixture with NaBH4 is 5 as the ketone with chiral center will give diastereoisomer with NaBH4
The isomer of ethanol is:
- a)Dimethyl ether
- b)Diethyl ether
- c)Methanol
- d)Acetone
Correct answer is option 'A'. Can you explain this answer?
The isomer of ethanol is:
a)
Dimethyl ether
b)
Diethyl ether
c)
Methanol
d)
Acetone
|
|
Pranavi Kulkarni answered |
The isomer of ethanol(CH3-CH2-OH) is dimethyl ether(CH3-O-CH3). This is a functional isomer of ethanol.
Explanation:
- Functional isomers are the ones with the same molecular formula but different functional groups.
- The molecular formula for dimethyl ether is C2H6O similar to ethanol.
- Dimethyl ether has the structural formula CH3OCH3 and ethanol has the structural formula CH3CH2OH.
- Therefore, dimethyl ether is the functional isomer of ethanol as both have the same molecular formula but one is ether and the other is alcohol.
Some meta-directing substituents in aromatic substitution are given. Which one is most deactivating? [NEET 2013]- a)–SO3H
- b)–COOH
- c)–NO2
- d)–C ≡ N
Correct answer is option 'C'. Can you explain this answer?
Some meta-directing substituents in aromatic substitution are given. Which one is most deactivating? [NEET 2013]
a)
–SO3H
b)
–COOH
c)
–NO2
d)
–C ≡ N
|
Anu Bajaj answered |
Decreasing order of deactivating effect of the given m-directing group is > NO2 > – CN > – SO3H > – COOH
—NO2 group is most deactivating group due to strong – E, – I and – M effects.
—NO2 group is most deactivating group due to strong – E, – I and – M effects.
How many structural isomers are possible with molecular formula C4H10O ?- a)3
- b)5
- c)7
- d)8
Correct answer is option 'C'. Can you explain this answer?
How many structural isomers are possible with molecular formula C4H10O ?
a)
3
b)
5
c)
7
d)
8
|
|
Preeti Iyer answered |
The formula that these isomers contain no rings or double bonds. The isomers must be alcohols and ethers.
Let's start by drawing the alcohols.
Start with four carbons in a row and put an OH group in every possible position.
This gives us
1. CH3CH2CH2CH2OH, butan 1-ol
and
2. CH3CH2CH(OH)CH3, butan-2-ol
Now use a 3-carbon chain with a CH3 on the middle carbon.
This gives
(CH3)2CHCH2OH, 2-methylpropan-1-ol
and
(CH3)3COH, 2-methylpropan-2-ol.
Now for the ethers.
Let's start with five atoms in a row.
This gives
CH3CH2CH2OCH3, 1-methoxypropane
and
CH3CH2OCH2CH3 , ethoxyethane
Finally, the only choice for a branched-chain ether is
(CH3)2CHOCH3 , 2-methoxpropane.
And there are your seven isomers of C4H10O.
A pair of enantiomers is possible for _______ isomer of 2,2-dibromobicyclo [2.2.1] heptane.
- a)cis
- b)trans
- c)both cis and trans
- d)none of the above
Correct answer is option 'A'. Can you explain this answer?
A pair of enantiomers is possible for _______ isomer of 2,2-dibromobicyclo [2.2.1] heptane.
a)
cis
b)
trans
c)
both cis and trans
d)
none of the above
|
Tejas Verma answered |
Only one pair of enantiomers is possible for cis-2,2-dibromobicyclo [2.2.1] heptane. The trans arrangement of one carbon bridge is structurally impossible. Such a molecule would have too much strain.
C3H6O represents an aldehyde and a ketone, is a type of:
- a)Chain isomerism
- b)Functional group isomerism
- c)Metamerism
- d)Position isomerism
Correct answer is option 'B'. Can you explain this answer?
C3H6O represents an aldehyde and a ketone, is a type of:
a)
Chain isomerism
b)
Functional group isomerism
c)
Metamerism
d)
Position isomerism
|
|
Preeti Iyer answered |
The aldehyde and ketone that can be represented by molecular formula C3H6O are propanal and propanone respectively.
Aldehyde - Propanal - CH3CH2CHO
Ketone - Propanone - CH3COCH3
These two carbon compounds are called functional isomers. They do not have the same physical properties since their functional group is different.
When hydrogen is present on one side of C=O group and other side is R, (RCHO), then it is an aldehyde group. When R is present on both sides of C=O group, then it is a ketone.
Direction (Q. Nos. 1 - 9) This section contains 9 multiple choice questions. Each question has four
choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.
Q.
- a)3
- b)5
- c)7
- d)9
Correct answer is option 'C'. Can you explain this answer?
Direction (Q. Nos. 1 - 9) This section contains 9 multiple choice questions. Each question has four
choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.
choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.
Q.
a)
3
b)
5
c)
7
d)
9
|
Kamna Science Academy answered |
The number of optically active isomers = 2n−1−2n−1/2 =23−1−23−1/2 =2.
Heterolytic cleavage is a way to cleave the:- a)Non-ionic bonds
- b)Ionic bonds
- c)Covalent bonds
- d)Polar bonds
Correct answer is option 'C'. Can you explain this answer?
Heterolytic cleavage is a way to cleave the:
a)
Non-ionic bonds
b)
Ionic bonds
c)
Covalent bonds
d)
Polar bonds
|
|
Rahul Bansal answered |
In heterolytic cleavage, a covalent bond breaks in such a way that one fragment gets both of the shared electrons. In homolytic cleavage, a covalent bond breaks in such a way that each fragment gets one of the shared electrons. The word heterolytic comes from the Greek heteros, "different", and lysis, "loosening".
The number of optical isomers possible for 2, 3-pentanediol is:
- a)2
- b)3
- c)4
- d)5
Correct answer is option 'C'. Can you explain this answer?
The number of optical isomers possible for 2, 3-pentanediol is:
a)
2
b)
3
c)
4
d)
5
|
|
Preeti Iyer answered |
2 optical centers.
Total optically active isomers =22
=4
Total optically active isomers =22
=4
Which of the following statements are correct?
I. A pair of positional isomers differs in the position of the same functional group.
II. A pair of. structural isomers have the same relative molar mass.
Ill. A pair of functional group isomers belongs to different homologous series.
- a)I, II and Ill
- b)I and Ill
- c)II and III
- d)I and II
Correct answer is option 'A'. Can you explain this answer?
Which of the following statements are correct?
I. A pair of positional isomers differs in the position of the same functional group.
II. A pair of. structural isomers have the same relative molar mass.
Ill. A pair of functional group isomers belongs to different homologous series.
II. A pair of. structural isomers have the same relative molar mass.
Ill. A pair of functional group isomers belongs to different homologous series.
a)
I, II and Ill
b)
I and Ill
c)
II and III
d)
I and II
|
|
Preeti Iyer answered |
According to me all statements are correct. For statement I, positional isomers have the same functional group. They just differ in the position of that group.
Statenmen II- Structural isomers have the same relative molar mass. Actually relative mass means the mass of one isomer is samee relative to another. Structural isomers differ in the structure of molecules. However they have the same molecular formula and hence; same molar mass.
Statement III- According to me, this statement is correct. As homologous series must contain the same functional group with the same physical & chemical properties. Also functional group isomers differ in the functional group attached with them. So, functional group isomers belong to different homologous series.
Statenmen II- Structural isomers have the same relative molar mass. Actually relative mass means the mass of one isomer is samee relative to another. Structural isomers differ in the structure of molecules. However they have the same molecular formula and hence; same molar mass.
Statement III- According to me, this statement is correct. As homologous series must contain the same functional group with the same physical & chemical properties. Also functional group isomers differ in the functional group attached with them. So, functional group isomers belong to different homologous series.
Which of the following are not functional isomers of each other?
- a)CH3CH2NO2 and CH3CH2ON=O
- b)C2H5CHO and CH3COCH3
- c)CH3CH2NH2 and CH3NHCH3
- d)C3H7NH2 and (CH3)2CHNH2
Correct answer is option 'D'. Can you explain this answer?
Which of the following are not functional isomers of each other?
a)
CH3CH2NO2 and CH3CH2ON=O
b)
C2H5CHO and CH3COCH3
c)
CH3CH2NH2 and CH3NHCH3
d)
C3H7NH2 and (CH3)2CHNH2
|
|
Anjali Sharma answered |
Functional isomers are structural isomers that have the same molecular formula (that is, the same number of atoms of the same elements), but the atoms are connected in different ways so that the groupings are dissimilar or different functional groups.
10 amine to different 10 amines are not functional isomers.
Hence, option ′d′ is the answer.
The number of isomers of C6H14 is:- a)4
- b)5
- c)6
- d)7
Correct answer is option 'B'. Can you explain this answer?
The number of isomers of C6H14 is:
a)
4
b)
5
c)
6
d)
7
|
|
Anu Mukherjee answered |
**Explanation:**
To determine the number of isomers of C6H14, we need to consider the different ways in which carbon atoms can be arranged and the different ways in which hydrogen atoms can be distributed among these carbon atoms.
**1. Straight-chain isomers:**
The simplest isomer is the straight chain, where the carbon atoms are arranged in a linear sequence. For C6H14, there is only one straight-chain isomer.
**2. Branched-chain isomers:**
In branched-chain isomers, the carbon atoms are arranged in a branched manner. To determine the number of possible branched-chain isomers, we need to consider the different ways in which the branches can be arranged and the different positions at which the branches can be attached to the main chain.
In this case, one of the carbons in the straight chain can have three branches attached to it. We can have three different arrangements of these branches, which are:
- One branch attached to the first carbon and two branches attached to the second carbon.
- Two branches attached to the first carbon and one branch attached to the second carbon.
- Three branches attached to the first carbon and no branches attached to the second carbon.
For each of these arrangements, there are different possibilities for the positions of the branches along the main chain. Therefore, for the branched-chain isomers, there are a total of three possibilities.
**3. Cycloalkane isomers:**
Cycloalkanes are ring structures where the carbon atoms are arranged in a closed loop. For C6H14, we can have cycloalkane isomers with different ring sizes.
- Cyclohexane: In this case, all six carbon atoms form a single ring. There is only one possibility.
- Cyclopentane: In this case, five carbon atoms form a ring and the remaining carbon atom is attached to one of the carbons in the ring. There is only one possibility.
Therefore, the total number of isomers of C6H14 is the sum of the straight-chain isomer, branched-chain isomers, and cycloalkane isomers, which is 1 + 3 + 2 = 6.
Therefore, the correct answer is option **c) 6**.
To determine the number of isomers of C6H14, we need to consider the different ways in which carbon atoms can be arranged and the different ways in which hydrogen atoms can be distributed among these carbon atoms.
**1. Straight-chain isomers:**
The simplest isomer is the straight chain, where the carbon atoms are arranged in a linear sequence. For C6H14, there is only one straight-chain isomer.
**2. Branched-chain isomers:**
In branched-chain isomers, the carbon atoms are arranged in a branched manner. To determine the number of possible branched-chain isomers, we need to consider the different ways in which the branches can be arranged and the different positions at which the branches can be attached to the main chain.
In this case, one of the carbons in the straight chain can have three branches attached to it. We can have three different arrangements of these branches, which are:
- One branch attached to the first carbon and two branches attached to the second carbon.
- Two branches attached to the first carbon and one branch attached to the second carbon.
- Three branches attached to the first carbon and no branches attached to the second carbon.
For each of these arrangements, there are different possibilities for the positions of the branches along the main chain. Therefore, for the branched-chain isomers, there are a total of three possibilities.
**3. Cycloalkane isomers:**
Cycloalkanes are ring structures where the carbon atoms are arranged in a closed loop. For C6H14, we can have cycloalkane isomers with different ring sizes.
- Cyclohexane: In this case, all six carbon atoms form a single ring. There is only one possibility.
- Cyclopentane: In this case, five carbon atoms form a ring and the remaining carbon atom is attached to one of the carbons in the ring. There is only one possibility.
Therefore, the total number of isomers of C6H14 is the sum of the straight-chain isomer, branched-chain isomers, and cycloalkane isomers, which is 1 + 3 + 2 = 6.
Therefore, the correct answer is option **c) 6**.
Which among the following is not an aromatic compound(in specific)- a)Naphthalene
- b)Aniline
- c)Pyridine
- d)Tropolone
Correct answer is option 'C'. Can you explain this answer?
Which among the following is not an aromatic compound(in specific)
a)
Naphthalene
b)
Aniline
c)
Pyridine
d)
Tropolone
|
Sai Mishra answered |
Pyridine is heterocyclic aromatic compound. Whereas naphthalene and aniline are benzenoid aromatic compounds and tropolone is a non-benzenoid aromatic compound.
Organic compounds are broadly classified as
- a)alicyclic compounds and acyclic compounds
- b)Open chain compounds and linear chain compounds
- c)Cyclic compounds and alicyclic compounds
- d)Open chain compounds and closed compounds
Correct answer is option 'D'. Can you explain this answer?
Organic compounds are broadly classified as
a)
alicyclic compounds and acyclic compounds
b)
Open chain compounds and linear chain compounds
c)
Cyclic compounds and alicyclic compounds
d)
Open chain compounds and closed compounds
|
Arpita Nambiar answered |
The correct answer is option D
Organic compounds are broadly classified into open chain and closed chain compounds. Explanation: open chain compounds or acyclic compounds are otherwise called as aliphatic compounds.
Organic compounds are broadly classified into open chain and closed chain compounds. Explanation: open chain compounds or acyclic compounds are otherwise called as aliphatic compounds.
Which is not true regarding conformers of ethane?- a)Theoretically infinite conformers exist
- b)Staggered conformer has lower torsional strain than eclipsed one
- c)Increasing temperature increases the percentage of eclipsed conformer
- d)By precise experimental setup, staggered conformer can be separated out of system
Correct answer is option 'D'. Can you explain this answer?
Which is not true regarding conformers of ethane?
a)
Theoretically infinite conformers exist
b)
Staggered conformer has lower torsional strain than eclipsed one
c)
Increasing temperature increases the percentage of eclipsed conformer
d)
By precise experimental setup, staggered conformer can be separated out of system
|
|
Neha Joshi answered |
The correct answer is Option D.
Although conformers differ in potential energy and stability, the difference is so small that it does not allow their practical separation.
Although conformers differ in potential energy and stability, the difference is so small that it does not allow their practical separation.
For (i) I–, (ii) Cl–, (iii) Br–, the increasing order of nucleophilicity would be [2007]- a)Cl– < Br– < I–
- b)I– < Cl– < Br–
- c)Br– < Cl–< I–
- d)I– < Br– < Cl–
Correct answer is option 'A'. Can you explain this answer?
For (i) I–, (ii) Cl–, (iii) Br–, the increasing order of nucleophilicity would be [2007]
a)
Cl– < Br– < I–
b)
I– < Cl– < Br–
c)
Br– < Cl–< I–
d)
I– < Br– < Cl–
|
Harshitha Dey answered |
Nucleophilicity increases down the periodic table. I- > Br- > Cl- > F-
Direction (Q. Nos. 1-18) This section contains 18 multiple choice questions. Each question has four
choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.Q.
- a)3
- b)5
- c)6
- d)7
Correct answer is option 'B'. Can you explain this answer?
Direction (Q. Nos. 1-18) This section contains 18 multiple choice questions. Each question has four
choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.
choices (a), (b), (c) and (d), out of which ONLY ONE option is correct.
Q.
a)
3
b)
5
c)
6
d)
7
|
|
Naina Sharma answered |
C5 H10
Two times double bond can’t appear as it has asked alkene and not alkadiene. So, these are the only types of alkenes that can be formed which are structural isomers.
Two times double bond can’t appear as it has asked alkene and not alkadiene. So, these are the only types of alkenes that can be formed which are structural isomers.
[JEE Main 2013 Online Exam]- a)a
- b)b
- c)c
- d)d
Correct answer is option 'C'. Can you explain this answer?
[JEE Main 2013 Online Exam]
a)
a
b)
b
c)
c
d)
d
|
Om Desai answered |
In ethers, alcohols and amines, there is no double bond. However, esters have one double bond as same as monocarboxylic acid. So monocarboxylic acid is a functional isomer of ester (only for no. of carbon greater than 2. As we need to have at least 3 carbon atoms to form ester.)
- a)a
- b)b
- c)c
- d)d
Correct answer is option 'B'. Can you explain this answer?
a)
a
b)
b
c)
c
d)
d
|
|
Om Desai answered |
Double bond equivalent of C5H10O is 1. So, it will have either a double bond or a ring.So, it may be an aldehyde, ketone, alcohol( carbon chain having double bond) or epoxide.
Propyl ethanoate has 2 oxygen atoms. So, it will never be its isomer. HOwever option a and c will be its isomer as they are aldehyde.
Propyl ethanoate has 2 oxygen atoms. So, it will never be its isomer. HOwever option a and c will be its isomer as they are aldehyde.
Among the given compounds , the most susceptible to nucleophilic attack at the carbonyl group is: [2010]- a)CH3COOCH3
- b)CH3CONH2
- c)CH3COOCOCH3
- d)CH3COCI
Correct answer is option 'D'. Can you explain this answer?
Among the given compounds , the most susceptible to nucleophilic attack at the carbonyl group is: [2010]
a)
CH3COOCH3
b)
CH3CONH2
c)
CH3COOCOCH3
d)
CH3COCI
|
|
Rajat Kapoor answered |
CH3COCl
Lesser the electron density of acyl carbon atom, more will be the susceptibility of a nucleophile to attack it.
The Cl atom has strong - I effect and weakest +R effect because of the weak π-bond between the small sized C- atom and large sized Cl atom. Thus, in CH3COCl, acyl carbon has least electron density and hence, more susceptible for nucleophilic attack.
The organic reaction which proceeds through heterolytic bond cleavage are known as:- a)Covalent reactions
- b)Ionic reactions
- c)Free radical reaction
- d)Polar reactions
Correct answer is option 'B'. Can you explain this answer?
The organic reaction which proceeds through heterolytic bond cleavage are known as:
a)
Covalent reactions
b)
Ionic reactions
c)
Free radical reaction
d)
Polar reactions
|
Hansa Sharma answered |
In heterolytic bond cleavage the bond breaks unevenly and the shared pair of electrons is accommodated by one of the products, which produces one or more ions.As heterolytic bond cleavage gives ions. So the reaction which proceeds through heterolytic bond cleavage is an ionic reaction.
Hence B is the correct answer.
Aliphatic compound is the other name for- a)Acyclic compounds
- b)Alicyclic compounds
- c)Ring compounds
- d)Closed chain compounds
Correct answer is option 'A'. Can you explain this answer?
Aliphatic compound is the other name for
a)
Acyclic compounds
b)
Alicyclic compounds
c)
Ring compounds
d)
Closed chain compounds
|
Mansi Mukherjee answered |
Open chain compounds or acyclic compounds are otherwise called as aliphatic compounds.
Which of the following correctly ranks the cycloalkanes in order of increasing ring strain per methylene group? - a)Cyclopropane < Cyclobutane < Cyclopentane < Cyclohexane
- b)Cyclohexane < Cyclopentane < Cyclobutane < Cyclopropane
- c)Cyclohexane < Cyclobutane < Cyclopentane < Cyclopropane
- d)Cyclopropane < Cyclopentane < Cyclobutane < Cyclohexane
Correct answer is option 'B'. Can you explain this answer?
Which of the following correctly ranks the cycloalkanes in order of increasing ring strain per methylene group?
a)
Cyclopropane < Cyclobutane < Cyclopentane < Cyclohexane
b)
Cyclohexane < Cyclopentane < Cyclobutane < Cyclopropane
c)
Cyclohexane < Cyclobutane < Cyclopentane < Cyclopropane
d)
Cyclopropane < Cyclopentane < Cyclobutane < Cyclohexane
|
|
Rajesh Gupta answered |
The correct answer is Option B.
The C-C-C bond angles in cyclopropane (60o) and cyclobutane (90o) are much different than the ideal bond angle of 109.5o.This bond angle causes cyclopropane and cyclobutane to have a high ring strain. However, molecules, such as cyclohexane and cyclopentane, would have a much lower ring strain because the bond angle between the carbons is much closer to 109.5o.
The C-C-C bond angles in cyclopropane (60o) and cyclobutane (90o) are much different than the ideal bond angle of 109.5o.This bond angle causes cyclopropane and cyclobutane to have a high ring strain. However, molecules, such as cyclohexane and cyclopentane, would have a much lower ring strain because the bond angle between the carbons is much closer to 109.5o.
Which,of the following correctly lists the conformations of cyclohexane in order of increasing potential energies?- a)Chair < Boat < Twist boat < Half-chair
- b)Half-chair < Boat < Twist boat < Chair
- c)Chair < Twist boat < Half-chair < Boat
- d)Chair < Twist boat < Boat < Half-chair
Correct answer is option 'D'. Can you explain this answer?
Which,of the following correctly lists the conformations of cyclohexane in order of increasing potential energies?
a)
Chair < Boat < Twist boat < Half-chair
b)
Half-chair < Boat < Twist boat < Chair
c)
Chair < Twist boat < Half-chair < Boat
d)
Chair < Twist boat < Boat < Half-chair
|
|
Riya Banerjee answered |
Correct answer is option D
Chair >Twist boat > Boat > Half-chair
above is the stability order of
the conformed.
Stability is inversely proportional to potential energy.
the conformed.
Stability is inversely proportional to potential energy.
The correct order of increasing bond length of C – H, C – O, C – C and C = C is : [2011]- a)C – H < C = C < C – O < C – C
- b)C – C < C = C < C – O < C – H
- c)C – O < C – H < C – C < C = C
- d)C – H < C – O < C – C < C = C
Correct answer is option 'A'. Can you explain this answer?
The correct order of increasing bond length of C – H, C – O, C – C and C = C is : [2011]
a)
C – H < C = C < C – O < C – C
b)
C – C < C = C < C – O < C – H
c)
C – O < C – H < C – C < C = C
d)
C – H < C – O < C – C < C = C
|
Ritika Khanna answered |
Bond length order is
Organic compounds can be classified even based upon the function groups. Identify the one which is not a functional group- a)Isocyanide
- b)Isocyano
- c)Carboxyl
- d)Carbonyl
Correct answer is option 'A'. Can you explain this answer?
Organic compounds can be classified even based upon the function groups. Identify the one which is not a functional group
a)
Isocyanide
b)
Isocyano
c)
Carboxyl
d)
Carbonyl
|
|
Mansi Mukherjee answered |
Isocyanide is a compound and it is not a functional group.
A sequential account of each step, describing details of electron movement, energetics during bond cleavage and bond formation, and the rates of transformation of reactants into products (kinetics) is referred to as:- a)Reaction mechanism
- b)Reaction kinetics
- c)Thermodynamics
- d)Equation
Correct answer is option 'A'. Can you explain this answer?
A sequential account of each step, describing details of electron movement, energetics during bond cleavage and bond formation, and the rates of transformation of reactants into products (kinetics) is referred to as:
a)
Reaction mechanism
b)
Reaction kinetics
c)
Thermodynamics
d)
Equation
|
Rajesh Nirfarake answered |
Reaction mechanism is a stepwise description of each and every step involved in reaction so the correct option is A
What is wrong about enantiomers of 2-chloropropanoic acid?- a)Have same solubility in water
- b)Have same pKa value
- c)Have same refractive indices
- d)Have same rate of reactions with (+)-2-butanol
Correct answer is option 'D'. Can you explain this answer?
What is wrong about enantiomers of 2-chloropropanoic acid?
a)
Have same solubility in water
b)
Have same pKa value
c)
Have same refractive indices
d)
Have same rate of reactions with (+)-2-butanol
|
|
Preeti Iyer answered |
The correct answer is option D.
Pair of enantiomers react differently with pure enantiomers of other compounds.
Pair of enantiomers react differently with pure enantiomers of other compounds.
Which nomenclature is not according to IUPAC system? [2012]
- a)
- b)
- c)
2-Methyl-3-phenylpentane
- d)
5-oxohexanoic acid
Correct answer is option 'A'. Can you explain this answer?
Which nomenclature is not according to IUPAC system? [2012]
a)
b)
c)
2-Methyl-3-phenylpentane
d)
5-oxohexanoic acid
|
Rajesh Datta answered |
In IUPAC system of nomenclature, preference is given to multiple bond than halogen substituent, so the correct name of
is 3-Bromoprop-1-ene.Number of chiral carbons in β - D - (+) - glucose is [2004]- a)five
- b)six
- c)three
- d)four
Correct answer is option 'A'. Can you explain this answer?
Number of chiral carbons in β - D - (+) - glucose is [2004]
a)
five
b)
six
c)
three
d)
four
|
Krish Patel answered |
Carbon atoms from C1 to C5 are chiral
The minimum number of C atoms required for a hydrocarbon to exhibit optical isomerism:
- a)4
- b)5
- c)6
- d)7
Correct answer is option 'D'. Can you explain this answer?
The minimum number of C atoms required for a hydrocarbon to exhibit optical isomerism:
a)
4
b)
5
c)
6
d)
7
|
Varun Kapoor answered |
The minimum number of C atoms required for a hydrocarbon to exhibit optical isomerism = 7
A hydrocarbon X is optically. X upon hydrogenation gives an optically inactive alkane Y. Which of the following pair of compounds can be X and Y respectively?- a)4-methyl-2-hexene and 3-methyl hexane
- b)3-methyl-1-pentene and 3-methyl pentane
- c) 4-methyl cyclopentene and methyl cyclopentane
- d)2-methyl-1-butene and 2-methyl butane
Correct answer is option 'B'. Can you explain this answer?
A hydrocarbon X is optically. X upon hydrogenation gives an optically inactive alkane Y. Which of the following pair of compounds can be X and Y respectively?
a)
4-methyl-2-hexene and 3-methyl hexane
b)
3-methyl-1-pentene and 3-methyl pentane
c)
4-methyl cyclopentene and methyl cyclopentane
d)
2-methyl-1-butene and 2-methyl butane
|
|
Pooja Shah answered |
The correct answer is Option B.
The optically active hydrocarbon X is 3-methyl-1-pentene CH2=CH−CH(CH3)CH2CH3. On catalytic hydrogenation, it forms 3-methyl pentane CH3CH2CH(CH3)CH2CH3, which is optically inactive.
The optically active hydrocarbon X is 3-methyl-1-pentene CH2=CH−CH(CH3)CH2CH3. On catalytic hydrogenation, it forms 3-methyl pentane CH3CH2CH(CH3)CH2CH3, which is optically inactive.
Which among the following does not exhibit geometric isomerism- a)1-hexene
- b)2-hexene
- c)3-hexene
- d)4-hexene
Correct answer is option 'A'. Can you explain this answer?
Which among the following does not exhibit geometric isomerism
a)
1-hexene
b)
2-hexene
c)
3-hexene
d)
4-hexene
|
Abhiram Choudhary answered |
Alkenes like 1-hexene when flipped from top to bottom they have identical structures and also they have C=CH2 unit which does not exist as cis- trans isomers.
How many different stereoisomers exist for 1-chloro-2-(3-chlorocyclobutane) ethene?a)2b)4c)5d)7Correct answer is option 'B'. Can you explain this answer?
|
|
Om Desai answered |
So, there are 4 isomers of given compound.
Which among the following is a very unstable and reactive species:- a)Carbaanion
- b)Polar ions
- c)Carbocation
- d)Free radical
Correct answer is option 'C'. Can you explain this answer?
Which among the following is a very unstable and reactive species:
a)
Carbaanion
b)
Polar ions
c)
Carbocation
d)
Free radical
|
Geethika Reddy answered |
Actually carbanions are filled with octet, so they are stable and less reactive, in case of polar ions already they are stable, and free radicle is heptet i.e, near to octet whereas carbocation is sextet in nature, so in order to gain to octet it is more reactive and less stable
Which of the following is not chiral ? [2006]- a)2, 3- Dibromopentane
- b)3-Bromopentane
- c)2-Hydroxypropanoic acid
- d)2-Butanol
Correct answer is option 'B'. Can you explain this answer?
Which of the following is not chiral ? [2006]
a)
2, 3- Dibromopentane
b)
3-Bromopentane
c)
2-Hydroxypropanoic acid
d)
2-Butanol
|
|
Suhana Agrawal answered |
3-Bromopentane is a symmetric compound hence,achiral.
If there is no rotation of plane polarised light by a compound in a specific solvent, though to be chiral, it may mean that [2007]- a)the compound is certainly meso
- b)there is no compound in the solvent
- c)the compound may be a racemic mixture
- d)the compound is certainly a chiral.
Correct answer is option 'A'. Can you explain this answer?
If there is no rotation of plane polarised light by a compound in a specific solvent, though to be chiral, it may mean that [2007]
a)
the compound is certainly meso
b)
there is no compound in the solvent
c)
the compound may be a racemic mixture
d)
the compound is certainly a chiral.
|
|
Rocky Handsome answered |
Meso compound does not rotate plane polarised light. Compound which contains tetrahedral atoms with four different groups but the whole molecule is a chiral, is known as meso compound. It possesses a plane of symmetry and is optically inactive.
•One of the asymmetric carbon atoms turns the plane of polarised light to the right and other to the left and to the same extent so that the rotation due to upper half is compensated by the lower half, i.e., internally compensated, and finally there is no rotation of plane polarised light.
•One of the asymmetric carbon atoms turns the plane of polarised light to the right and other to the left and to the same extent so that the rotation due to upper half is compensated by the lower half, i.e., internally compensated, and finally there is no rotation of plane polarised light.
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