Staggered and eclipsed conformation of ethane. Staggered ethane belongs to the D 3d point group.

Staggered and eclipsed conformation of ethane According to the traditional explanation [] widely accepted among organic chemists [3–5], the ~2. Go to Animation CA2. At room temperature, these two conformatio easily change into one another. Remember, in eclipsed conformations, all the atoms/groups on the neighboring carbons are aligned, Newman and Sawhorse projections This is due to the fact that in the eclipsed conformation, the hydrogen atoms are directly aligned with each other, leading to increased steric hindrance and torsional strain due to repulsion between the electron clouds of the hydrogen The staggered conformation of ethane is lower in energy than the eclipsed conformation by about 3 kcal/mole (~12 kJ/mol). Due to this rotation, called the internal rotation, ethane has two major conformations — staggered and eclipsed. The extra 12 kJ/mol of energy present in the eclipsed conformation of ethane is called torsional strain. The Newman projection corresponding to forms A-D is shown below (5-8). The staggered form of ethane has: Q. The dihedral angle between the hydrogen atoms of 2 methyl groups in staggered conformation of ethane is. Back to Learn by watching this video about Staggered and Eclipsed Conformations of Ethane and Propane at JoVE. We also saw that CH4is a perfect tetrahedron, with H-C-H bond angles of 109. Why is a staggered conformer more stable than an eclipsed conformer? Staggered conformation of ethane is more stable than the eclipsed conformation because in staggered form the electron clouds of carbon – hydrogen bonds are as far apart as possible. Ethane (eclipsed conformation) belongs to the D3h point group. B. 3. No, eclipsed and staggered conformations of ethane cannot be isolated. We can show this by wedge and dash representation, sawhorse projection, and most At any given instant, about 99% of ethane molecules have an approximately staggered conformation and only about 1% are near the eclipsed conformation. The strain in the eclipsed conformation of ethane is due to . Here, the electrons clouds of carbon-hydrogen bonds are as far as possible. configuration. In the staggered conformation, all of the C-H bonds on the front carbon are positioned The correct statement regarding the comparison of staggered and eclipsed conformations of ethane is: 1. Q. Ethane can have two possible conformations, the staggered conformation and the eclipsed conformation. asked Jun 6, 2018 in Chemistry by Golu (106k points) hydrocarbons; class-11 +1 vote. Similar questions. Reason: Staggered form has the least tor Depending on whether the hydrogens on the carbon atoms are aligned or not, there are two distinct conformations called eclipsed and staggered. Check A The eclipsed conformation of ethane is 12 kJ/mol less stable than the staggered. The staggered conformation is more stable. This process can be continued all around the 360°circle, with three possible eclipsed conformations and three staggered conformations, in addition to an The staggered conformation is more stable by 12. Ethane (staggered) belongs to the D3d group, ethane (eclipsed) is in the D3h group, chloroethane (staggered) belongs to the C3v group, and 1,2-dichloroethane (staggered anti) is in the C2h group. Butane, as a more complex molecule than ethane, has an eclipsed conformation of the maximum energy and a staggered conformation of the minimum energy (anti conformation). Wrong Answer. (5 Marks) Reason: Staggered form has the least torsional strain and eclipsed form has the maximum torsional strain. What is the energy difference between the staggered and eclipsed conformations of ethane? asked Oct 24, 2020 in Chemistry by NehalJain (93. In a more visual representation, it would look like this: Ethane is a classical example to study stereochemistry. The extra 12 kJ/mol of The staggered conformation of ethane is more stable than eclipsed conformation. 5 kJ mol-1 more stable than the eclipsed conformation. This process can be continued all around the 360°circle, with three possible eclipsed conformations and three staggered conformations, in addition to an Eclipsed Conformation: The eclipsed conformation for a molecule is one in which the groups attached to the front and back atoms are at a minimal distance from each other. The eclipsed and staggered conformation of ethane is due to - 05:22. [1] Such a conformation can exist in any open chain, single chemical bond connecting two sp 3 The highest-energy, least stable conformation is the one in which the six C–H bonds are as close as possible— eclipsed in a Newman projection. 11. Suggest Corrections. In the case of butane, however, two conformations are not enough to The correct answer is Magnitude of torsional strain depends upon the angle of rotation about C-C. A conformation analysis is an investigation of the energy differences and relative stabilities of the different conformations of a compound. (ii) Newman projections of ethane . The staggered conformation of ethane is more stable than the eclipsed conformation due to reduced Like for any other tetrahedral carbon, the rotation about the single bond gives two distinct sets of conformation: staggered and eclipsed. Understanding Ethane Structure : Ethane (C2H6) consists of two carbon atoms (C) bonded to each other, with three hydrogen atoms (H) attached to each carbon. Rotation of one conformer by an angle between 0° to 60° generates _____. com Figure 3. View Ethane’s eclipsed conformation is 3 kcal/mol less stable than the staggered conformation. The Kohn-Sham total energy rotation (E rot) for conversion of ethane from staggered to eclipsed conformation was calculated in the gas phase and the geometries were fully optimized. When the substituents on the two carbons are the maximum distance from each other looking down the bond the conformation is staggered (Figure 3. The staggered conformer is lower in energy than the eclipsed conformer. Staggered conformation of ethane is most stable while eclipsed conformation is least stable. Torsional strain is the destabilization that results from eclipsed bonds. In the eclipsed conformation, the hydrogens on the front carbon block (or To determine the staggered and eclipsed conformers of ethane, we need to understand the molecular structure and the concept of conformers. Q3. In the staggered conformation, all of the C-H bonds on the front How to represent the staggered and eclipsed conformations of ethane. 11). In the eclipsed form, the electron densities Q. The staggered conformation is an arrangement in which the substituents of neighboring carbons are located as far from each other as Learn by watching this video about Staggered and Eclipsed Conformations of Ethane and Propane at JoVE. The eclipsed conformation of ethane is more stable than staggered conformation because eclipsed conformation has no torsional strain. 5 kJ/mol than the eclipsed one. The conformations of ethane have only horizontal, vertical and dihedral mirrors. org/science/organic-chemistry/bond-line-st Conformationally, butane is more complex than ethane or propane. Alkanes that are more complex than ethane, like propane and butane have a greater variety in possible conformers and their 3. Inversion Center. . In a previous post we discussed how we know that methane CH4 is tetrahedral (See: How Do We Know That Methane Is Tetrahedral), as this shape maximizes the distance between the repulsive bonding electron pairs. ltbr. 1. The principal rotation axis has the highest "order" -- C 3 > C 2 in this case. The staggered conformation of ethane is more stable than eclipsed conformation, because staggered conformation has no torsional strain. Another 60°rotation returns the molecule to a second eclipsed conformation. conformation A chiral alkyne A with molecular formula C_6H_10 is reduced with H_2 and Lindlar catalyst to B having the R configuration at its stereogenic center. The staggered conformation is the most stable (lower in energy) and the eclipsed conformation is the least stable (higher in energy) due to repulsive interactions between the Newman and Sawhorse projections Final answer: Each molecule has a unique point group. View Solution. The staggered conformation of ethane is more stable than eclipsed conformation, because comparatively staggered conformation has no torsional strain. In the eclipsed form, the electron densities on the C − H bonds are closer together than they are in the staggered form. As shown above, they are closer in the eclipsed form and thus experience greater repulsion. Introduction; Identity; Reflection; JEE Main 2021: Staggered and eclipsed conformers of ethane are: (A) Polymers (B) Rotamers (C) Enantiomers (D) Mirror images. But as all the substituents are hydrogen in ethane's case, all staggered and eclipsed form are equivalent respectively. A three-dimensional model of ethane in eclipsed conformation. There are 3 σ v planes and a σ h plane. [Eclipsed hydrogens in the graph are shown in the graph in red Energy difference between eclipsed and staggered form of ethane is (A) 12. Staggered conformation is the most stable among other possible conformations for ethane. Click on the energy diagrams to see a movie of the conformers with their relative energies. REPRESENTATION OF ECLIPSED AND STAGGERED CONFORMATION: Newman projections: • In this projection, out of the two carbon atoms present in ethane one which is nearer is shown as a dot whereas the rear carbon atom is represented as a circle. Energy barrier between staggered and eclipsed ethane is : Q. This process can be (I) The staggered conformation of a molecule is that conformation where the dihedral angle between the bonds at each atom of carbon-carbon bond is 60°, 180°,300°. Next, we will do a conformation analysis of ethane by using the Newman projections. Since there are three eclipsed conformations, we can say that each \(σ_{C-H}\)eclipsing interaction is The rotation of ethane molecules around its carbon-carbon single bond. (A) Both assertion and reason are correct and the reason is the correct explanation for assertion. In organic chemistry, a staggered conformation is a chemical conformation of an ethane-like moiety abcX–Ydef in which the substituents a, b, and c are at the maximum distance from d, e, and f; this requires the torsion angles to be 60°. As the rotation around the \(\mathrm{C-C}\) bond continues, these two conformations repeat. b. Thus, there are minimum repulsive forces, minimum energy and maximum stability of the molecule. 9 Kcal/mole (12 kJ/mole). View Solution; Staggered and eclipsed form of ethane are. However, in the case of butane there are two different valleys, and two different peaks. The reason for this in ethane is not wholly clear, but doubtless depends on the fact that, in the staggered conformation, the \(C-H\) bonding electrons are as far away from one another as possible and give the least interelectronic The staggered conformation of ethane is a more stable, lower energy conformation than the eclipsed conformation because the eclipsed conformation involves unfavorable interactions between hydrogen atoms. At any given instant, about 99% of ethane molecules have an approximately staggered conformation and only about 1% are near the eclipsed conformation. The eclipsed conformation is said to suffer torsional strain because of repulsive forces between electron pairs in the C―H bonds of adjacent carbons. 0 kcal/mol. Conformation of Ethane • When an ethane molecule rotates about it's carbon- carbon single bond two extreme conformations can be result, the staggered and eclipsed conformation. 1. Hence the rotation about carbon-carbon single bond is neither Ethane (staggered conformation) belongs to the D3d point group due to the presence of a C3 rotational axis, 3 C2 perpendicular axes and a center of symmetry. In the previous post [see: Staggered vs Eclipsed Conformations of Ethane] we saw that ethane has two important conformational isomers, depending on Eclipsed Ethane (CH 3 CH 3, with H - lined up) & Staggered Ethane (CH 3 CH 3, with H - not lined up) top. (ii) the electron clouds come closer when the staggered form changes to the eclipsed form. Given sublimation and ionization energy of Na are 108 kJ/mol and 496 kJ/mol respectively and bond dissociation energy required to make one mole chlorine atoms and its electron affinity energy are 122 kJ/mol and -349 kJ/mol. 14 The eclipsed conformation of ethane shown below in 'B' is higher in energy, i. Conformations: Conformers are compounds that differ by orientation of atoms in space; they are interconvertible via rotation about single bonds. 5 kJ/mol than the eclipsed conformation, which is the energy maximum for ethane. Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front Staggered conformation of ethane is more stable than the eclipsed conformation because in staggered form, the electron clouds of carbon – hydrogen bonds are as far apart as possible. Representation of Eclipsed and Staggered Conformation; Recommended Videos; Frequently Asked Questions – FAQs; Conformational Isomers. Proper Rotation Axes. This barrier is more than RT ( » 0. The two conformational energy diagrams shown below are staggered ethane and eclipsed ethane. In chemistry an eclipsed conformation is a conformation in which two substituents X and Y on adjacent atoms A, B are in closest proximity, implying that the torsion angle X–A–B–Y is 0°. In the Every species has one and only one identity. The eclipsed conformation of ethane is more stable than staggered conformation because eclipsed conformation has no torsional strain2. Torsional strain in molecules is a result of repulsion between the groups. So there are minimum repulsive forces. There are two types of conformations: staggered conformation and eclipsed conformation. This is an inherent limitation associated with representing a 3-D structure in two dimensions. The dihedral angle of the least stable conformer of ethane is _____. A) H ?A (a) Angle strain (b) spring tension (c) steric strain (d) torsional strain In different conformations of butane, which of the The dihedral angle between the hydrogen atoms of two methyl groups in staggered conformation of ethane is . This energy Q. Also, the effect of the ZPE on rotational barrier was analyzed. In fact, the staggered conformation corresponds to the energy minimum of alkane and the eclipsed The staggered conformer: The eclipsed conformer: Now in a full 2π rotation you will encounter both the staggered and the eclipsed form 3 times each, alternating every π/3 radians. Justify the statement. 4 The dihedral angle-potential energy diagram of butane. For ethane and its derivatives, the staggered conformations are more stable than the eclipsed conformations. (b) the staggered conformation of ethane is more stable than eclipsed conformation, because staggered conformation has the eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has torsional strain. constitution d. 2. Check Answer and Solution Figure 3. There is only one C 3 in ethane. The staggered conformation of ethane is more stable by 12. 5K Views. This corresponds to a The two conformations shown for ethane are the fully eclipsed conformation, where the dihedral angle is equal to \(0^{\circ}\), and the staggered conformation, where the dihedral angle is \(60^{\circ}\). In the staggered conformation, all of the C-H bonds on the front 3. It is called the "more stable eclipsed conformation". The staggered conformation of ethane is a more stable, lower energy conformation than the eclipsed conformation because the eclipsed conformation involves Staggered conformation of ethane is more stable than the eclipsed conformation because in staggered form the electron clouds of carbon – hydrogen bonds are as far apart as possible. Reason: Staggered form has the least tor asked Apr 18, 2022 in Chemistry by aryam ( 122k points) Figure 3. A sawhorse projection Ethane (staggered) Methane; Going Further. khanacademy. Point groups; Applications; This project supported by NSF-DUE #0536710 HTML5 • Java. the atoms of interest across one bond are on opposite sides along the vertical molecular plane. 5 kJ mol -1 (B) 15. 55 KJ/mol. This one is a little more stable than the other eclipsed conformation, for reasons that we will look into shortly. Rotation around carbon-carbon single bond of ethane is not completely free. Complete step by step answer: The molecular formula for ethane is The staggered conformation of ethane is a more stable, lower energy conformation than the eclipsed conformation because the eclipsed conformation involves unfavorable interactions between hydrogen atoms. The eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has a 5. structure b. The lowest energy conformation of ethane, shown in the figure above, is called the ‘staggered’ conformation. with ethane, the staggered conformations of butane are energy 'valleys', and the eclipsed conformations are energy 'peaks'. Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front The correct statement regarding the comparison staggered and eclipsed conformation of ethane, A. Show transcribed image text There are 2 steps to solve this one. Remember, in eclipsed conformations, all the atoms/groups on the neighboring carbons are aligned, whereas for the staggered conformations, the atoms/groups are at 60 o: The incorrect statement regarding conformations of ethane is (1) Ethane has infinite number of conformations (2) The dihedral angle in staggered conformation is 60° (3) Eclipsed conformation is the most stable conformation (4) The conformations of ethane are interconvertible to In other words, a molecule cannot avoid an eclipsed conformation even though the energy of this conformation is higher than the staggered conformations. • The three hydrogen atoms attached to each carbon atom are represented with the help of three lines The eclipsed and staggered forms of ethane are said to differ in: a. Hence, t he staggered form of ethane has minimum repulsive forces and minimum energy. 1: A 3D Model of Staggered Ethane. Assertion : Staggered conformation of ethane is 12. Staggered form has the least torsional strain and the eclipsed form has the maximum torsional strain so, the staggered conformation of ethane is more stable than the eclipsed conformation. [1] It is the opposite of an eclipsed conformation, in The eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has torsional strain. Like for any other tetrahedral carbon, the rotation about the single bond gives two distinct sets of conformation: staggered and eclipsed. 9 kcal/mol, which is the activation energy (E a) required to proceed from one staggered conformation to the closest eclipsed conformation. This process can be Different conformations mainly deal with staggered and eclipsed conformations. To depict See more The lowest energy conformation of ethane, shown in the figure above, is called the ‘staggered’ conformation. e. The dihedral angle between them is 0°, 120°, 240°. Ethane (Eclipsed) Pointgroup Flow Chart . Eclipsed conformation (image right in Newman projection) Staggered conformation. Reason: Staggered form has the least torsional strain and the eclipsed form has the maximum In staggered form of ethane, the electron clouds of carbon-hydrogen bonds are as far apart as possible. In the staggered conformation, the C-H bonds on the rear carbon lie between those on the front carbon with dihedral angles of 60 degrees. 10 – An Eclipsed Conformation of Ethane. As with ethane, the staggered conformations of butane are energy 'valleys', and the eclipsed conformations are energy 'peaks'. 2 Conformation Analysis of Ethane. That is due to the minimized repulsion between bond electron pairs of the C-H bonds. Results and Discussion. Its cause has been the subject of controversy, but the major factor is an interaction Ball-and-stick model of ethane in an "eclipsed conformation". • Here we will use Newman NEET 2016: The correct statement regarding the comparison of staggered and eclipsed conformations of ethane, is: (A) The eclipsed conformation of etha The correct statement regarding the comparison staggered and eclipsed conformation of ethane, A. The correct statement the comparison of staggered and eclipsed conformations of ethan is: 2. These structures are degenerate. Specifically, the negatively charged electrons in the bonds repel each other most when the bonds line up. In an organic molecule, free rotation about the carbon-carbon single bond results in energetically different conformers of the molecule. In the case of ethane, the staggered and eclipsed conformations can sufficiently describe the features of its conformational analysis. 9 kcal/mol) The most stable conformation of ethane has all six C–H bonds away from each other (staggered) • The least stable conformation has all six C–H bonds as close as possible (eclipsed) in a Newman projection – energy due to torsional strain 5 In conformational isomers of ethane, the angle between the C-H bonds of 2 carbons can be anything between 0 and 360. It is because of very small energy difference between these two conformations. Reason : The two conformations of ethane cannot be separated at room temperature. Next: Conformations of butane. So, the correct answer Newman projection formula for different conformations of ethane: When an ethane molecule rotates about its carbon – Carbon single bond, two extreme conformations can result in the staggered conformation and the eclipsed conformation. This process can be continued all around the 360°circle, with three possible eclipsed conformations and three staggered conformations, in addition to an At room temperature, the eclipsed and staggered form of ethane cannot be isolated because: View Solution. conformation. D nd | D nh | D n Pointgroups How useful was this page? Click on a star to rate it! Sawhorse and newman projections of ethane: Conformation in which hydrogen atoms attached to two carbons are aligned exactly behind the H of first carbon as the projection of its bonds with H atoms, is called eclipsed conformation and conformation in which hydrogens are as far apart as possible is known as the staggered conformation. On the other hand, when the staggered form changes into the eclipsed form, the electron clouds of the carbon-hydrogen bonds come closer to each other resulting in increase Since rotation around the C-C bond of ethane is continuous, there are an infinite number of conformations, but only two are of major interest. Thus , there are minimum repulsive forces, minimum energy and maximum stability of the molecule. Let us understand the fundamentals of conformation with the example of ethane. The eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has a It is clearly different from the other eclipsed conformation. This is because any two hydrogen atoms on adjacent carbon atoms of staggered conformation are maximum apart while in eclipsed conformation, they cover or eclipse each other in space. Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses. Ethane has infinitely many conformations, but the most stable one is called staggered. Improper Rotation Axis. the atoms of interest across one bond are on the same side along the vertical molecular plane. If H 0 f of NaCl(s) is -411 kJ/mol. eclipsed conformation CC CH3CH3 H H HH CH3 HH CH3 HH sawhorse representation H CH3 H 2 3 H Newman projection CH3 Stability of conformation : In staggered form of ethane , the electron clouds of carbon-hydrogen bonds are as far apart as possible. Energy minima occur at staggered conformations, and energy Staggered form of ethane is more stable than the eclipsed conformation by about 12. The eclipsed conformation of ethane is less stable than the staggered conformation by 3 kcal/mol. 3. View Solution; A dihedral angle HCH in staggered conformation of C 2 H 6 6. In the staggered conformation, all of the C-H bonds on the front carbon are positioned at an angle of 60° relative to the C-H bonds The staggered conformation of ethane permits maximum possible separation of the electron pairs of the six carbon – hydrogen bonds. The staggered conformation of ethane is lower in energy than the eclipsed conformation by about 3 kcal/mole (~12 kJ/mol). This is due to the fact that in the eclipsed conformation, the hydrogen atoms are directly aligned with each other, leading to increased steric hindrance and torsional strain due to repulsion between the electron clouds of the hydrogen atoms. The eclipsed and staggered conformation of ethane is due to - asked Jan 1, 2022 in Chemistry by Baljeetkaur (34. Staggered Conformation of Ethane. Question: The eclipsed and staggered forms of ethane are said to differ in: structure constitution O molecular formula. Watch the next lesson: https://www. 6. However, the molecule may not spend much time in an eclipsed conformation. The two extreme conformation results in staggered and eclipsed conformation. 4K Views. For ethane, the conversion from a staggered conformation to eclipsed conformation requires 12 kJ/mol. Stability of conformation: (i) There are minimum repulsive forces, minimum energy and maximum stability in the staggered form of ethane. Q4. The electron concentrations on the C-H bonds are closer together in the In the previous post, we talked about the staggered and eclipsed conformations of ethane, and saw that these are the least and most stable conformations that differ by a 12 kJ/mol rotation barrier:. Therefore, these cannot be isolated. This is the lowest energy Rotation around carbon-carbon single bond of ethane is not completely free. The correct answer is Magnitude of torsional strain depends upon the angle of rotation about C-C. staggered conformation left, eclipsed conformation right in Newman projection The barrier to rotation around the C–C bond in ethane [] has long been considered as a textbook example of torsional strain. Energy minima. Improper Rotations Explained. Here's a simple way to represent this in text: Front Carbon: H - C - H | Back Carbon: H - C - H. An antiperiplanar conformation has a #180^@# dihedral angle, i. In the eclipsed conformation the torsional angle is minimised. As we’ve said, the difference in energy between the eclipsed and staggered conformations is 2. In the applied models the total energy of ethane is calculated as a function of the torsion angle φ, obtaining an energy minimum at the staggered Explore the conformational analysis of ethane in organic chemistry with Khan Academy's detailed video tutorial. The least stable conformation of ethane is called eclipsed; the eclipsed conformation represents the transition state upon going from one staggered The two conformational energy diagrams shown below are staggered ethane and eclipsed ethane. Eclipsed conformation is the least stable conformation of ethane due to repulsion between electron clouds of adjacent C-H bonds. Fill in the blanks: View Solution. The important point is that most organic structures At any given instant, about 99% of ethane molecules have an approximately staggered conformation and only about 1% are near the eclipsed conformation. Notice that when drawing the Newman projection of the eclipsed conformation of ethane, you cannot clearly draw the rear hydrogens exactly behind the front ones. View 18. Assertion :Staggered conformation of ethane is most stable while eclipsed conformation is least stable. These are the lowest energy structure, called the staggered conformation, and the highest energy Figure 3. The two conformations of ethane, staggered and eclipsed, are different and In the eclipsed conformation, the C-H bonds on the front and back carbons are aligned with each other with dihedral angles of 0 degrees. Its cause has been the subject of controversy, but the major factor is an interaction between C–H bonding orbitals on one carbon Hint: We know that the different spatial arrangements of atoms or groups of atoms which can be converted into one another by the rotation around single bonds are known as conformations or conformational isomers. Thus in staggered form, there is minimum repulsive forces, minimum energy and maximum Among the infinite number of conformations the staggered conformation in which hydrogen atoms are as far apart as possible is the most stable while the eclipsed conformation in which hydrogen atoms are perfectly eclipsed is the least stable; stabilities of the skew conformations lie in between these two extreme limits. The σs The energy barrier between staggered and eclipsed conformation in ethane molecule is 2. Figure \(\PageIndex{5}\): Ball-and-stick model of butane. The eclipsed conformation is destabilized by torsional strain. In staggered conformation projection, The hydrogens are drawn at an angle of 60 degrees. Thus staggered conformation of ethane is most stable and has lowest potential energy. 6 Kcal/mole) at room temperature (energy for free rotation) and less than 16-20 Kcal/mole (energy barrier for frozen rotation). The reason(s) for the special stability of staggered conformations has been surprisingly difficult to work out, with favorable orbital-orbital interactions and repulsive interactions both playing roles. The relative energies of each conformer are shown. 2 Conformational Analysis of Butane. This shape is called the "more stable eclipsed conformation". Such degeneracy is broken in butane, which has two different eclipsed conformations and two different staggered conformations. A The staggered conformation of ethane is Assertion: Staggered conformation of ethane is most stable while eclipsed conformation is least stable. Reason: Staggered form has the least torsional strain and the eclipsed form has the 11. The staggered conformation is the most stable of all possible conformations of ethane since the angles between C − H bonds on the front and rear carbons are maximized at 60 degrees. Its cause has been the subject of controversy, but the major factor is an interaction The difference in energy between the staggered and eclipsed conformation of ethane is 3. The Correct answer is: Eclipsed conformation is the most stable conformation. The eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has a The energy of the eclipsed conformation is approximately 3 kcal/mol higher than that of the staggered conformation. configuration c. Eclipsed conformation is the arrangement of Conformation vs Configuration; Conformations of ethane – Newman projection; Staggered ethane contains a main C 3 rotation axis with 3 C 2 rotation axis perpendicular to the C 3 axis, with 3 σ d planes. Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front Why is a staggered conformer more stable than an eclipsed conformer? Staggered conformation of ethane is more stable than the eclipsed conformation because in staggered form the electron clouds of carbon – hydrogen bonds are as far apart as possible. Thus, each pair of eclipsed C-H bond is worth 1. 5k points) class-12; The correct statement regarding the comparison of staggered and eclipsed conformations of ethane is: 1. The staggered conformation is the most stable of all possible conformations of ethane, since the angles between C-H bonds on the front and rear carbons are maximized at 60 degrees. This conformation is about 25 KJ/mol (6. com 4. The eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has torsional strain. D nd | D nh | D n Pointgroups The energy of the eclipsed conformation is approximately 3 kcal/mol higher than that of the staggered conformation. The barrier to rotation that results from this strain can be represented in a graph of potential energy versus degree of rotation in which the angle between C–H bonds on C-1 and C-2 (the dihedral angle) completes one revolution. In the staggered conformation, all of the C-H bonds on the front carbon are positioned at an angle of 60° relative to the C-H bonds Assertion: Staggered conformation of ethane is most stable while eclipsed conformation is least stable. The energy of the eclipsed conformation is approximately 3 kcal/mol higher than that of the staggered conformation. Eclipsed ethane contains a C 3 main rotation axis and 3 perpendicular C 2 axes. The methyl groups are anti to each other. The correct statement regarding the comparison of staggered and eclipsed conformations of ethane is: 1. 1 Kcal/mol) higher than the staggered conformation. 2. Ethane’s Conformations • There barrier to rotation between conformations is small (12 kJ/mol; 2. Because the angles between C-H bonds on the front and back carbons are maximised at 60 degrees, the staggered conformation is the most stable of all potential ethane conformations. Hence eclipsed ethane belongs to the D 3h point group. 5K 次观看. (a) Both A and R are true and R is the correct explanation of A (b) Both A and R are true but R is not correct explanation of A Ch 2 Ethane 5(10) Fig. Recap: Staggered, Eclipsed, Newman Projections, Dihedral Angle. The eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has a All the symmetry elements in ethane staggered form along with point group detection One more 60 rotation produces another staggered conformation called the anti conformation, where the two methyl groups are positioned opposite each other (a dihedral angle of 180 o). 5 °. Inversion Center -- located at center of molecule (0, 0, 0) The staggered conformation of ethane permits maximum possible separation of the electron pairs of the six carbon – hydrogen bonds. Find MCQs & Mock Test Take ethane as an example. An excerpt from Conformations of Ethane: Other articles where eclipsed conformation is discussed: hydrocarbon: Three-dimensional structures: with respect to the other—the eclipsed conformation is the least stable, and the staggered conformation is the most stable. Correct Answer. Click on The extra 12 kJ/mol of energy present in the eclipsed conformation of ethane is called torsional strain. The eclipsed and staggered forms of ethane are said to differ in: - Structure - Constitution - Molecular formula - Configuration - Conformation Conformation: Eclipsed and staggered forms of ethane differ in their conformation, as they have different spatial arrangements of atoms due to rotations around single bonds. In the eclipsed conformation of the Newman’s projection, Ques. e, more strained than the staggered conformation shown in ‘A. (II) In the eclipsed conformation the atoms bonded to carbons at each end of carbon-carbon bond are directly opposite to one another. Which points on the potential energy diagram represent the eclipsed conformation of ethane and staggered conformation of propane respectively ? Q. 5 kJ mol -1 (C) 14. ( b ) The staggered conformation of ethane is more stable than eclipsed conformation, because staggered conformation has no torsional strain. 18 The origin of torsional strain in ethane: Originally thought to be caused by repulsion between eclipsed hydrogen nuclei Alternatively, caused by repulsion between electron clouds of eclipsed C-H bonds Theoretical molecular orbital calculations suggest that the energy difference is not caused by destabilization of the eclipsed conformation but rather by Ethane has only two conformers of note - staggered and eclipsed. For ethane or propane, the three eclipsed forms are identical in energy, as are the three staggered forms. A C3 axis has no other axis collinear with it. In the eclipsed conformation of ethane, the hydrogen atoms attached to each carbon are in direct opposition to each other. D. 7: Conformations of Other Alkanes - Chemistry LibreTexts The energy change on each Occupied Molecular Orbital as a function of rotation about the C-C bond in ethane was studied using the B3LYP, mPWB95 functional and MP2 methods with different basis sets. 5 kJ mol -1 (D) 12. We have found that σ and π energies contribution stabilize a staggered conformation. Looking at a space filling model of ethane, it seems that the overall shape difference between staggered and eclipsed ethane is pretty small. 5 J mol -1. What is its approximate Also draw staggered & eclipsed conformation of ethane. 1 answer. There can be infinite possibilities of a The eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has torsional strain. The staggered conformation (dihedral angles = 60 o) is more stable than the eclipsed conformation (dihedral angles = 0 o). The gauche conformation is a higher energy valley than the anti conformation due to steric strain, which is the repulsive interaction The energy of the eclipsed conformation is approximately 3 kcal/mol higher than that of the staggered conformation. molecular formula e. 7k points) class-12; stereoisomerism; At any given instant, about 99% of ethane molecules have an approximately staggered conformation and only about 1% are near the eclipsed conformation. Ethane (Staggered) Pointgroup Flow Chart . There are also two eclipsed conformations (anticlinal), which represent local energy maxima, and two staggered conformations (gauche), which represent local energy minima. In the staggered conformation, all of the C-H bonds on the front carbon are positioned at an angle of 60° relative to the C-H bonds on the back carbon. Staggered ethane belongs to the D 3d point group. In the staggered conformation, the hydrogen atoms on the front and back carbons are not in line with each other, but are instead 'staggered'. 9 kcal/mol higher energy of eclipsed (E) versus staggered (S) conformation arises from greater steric repulsion in the former, mainly caused Staggered conformation image right in Newman projection Eclipsed conformation. This process can be continued all around the 360°circle, with three possible eclipsed conformations and three staggered conformations, in addition to an infinite number of The highest energy conformation is the eclipsed conformation with the two methyl groups eclipsed. top. Reason: Staggered form has the least torsional strain and the eclipsed form has the maximum torsional strain. So The 12 kJ/mol of extra energy in the eclipsed conformation of ethane is called torsional strain. Figure: Staggered and Eclipsed Conformation of Ethane. A synperiplanar conformation has a #0^@# dihedral angle, i. Sawhorse projections for the eclipsed and 1. ← Prev Question Next Question →. Torsional strain. Ethane (D 3d) Reflection Planes. Since eclipsed conformation has a greater potential energy due to torsional strain, it is less stable than the staggered conformation. If we observe the ball and stick model of ethane and rotate one carbon atom keeping another carbon atom stationary about the C-C axis. In the previous post [see: Staggered vs Eclipsed Conformations of Ethane] we saw that ethane has two important conformational isomers, depending on the orientation of the two methyl groups along the C–C bond. (a) the eclipsed conformation of ethane is more stable than staggered conformation even though the eclipsed conformation has torsional strain. ygkud nlyeyy sfmty qpdvub ajqt tesav pbu bowa qflnvjl jgrj