Question

Discuss the Energy/Angle Strain and Stability based on the table below of Sawhorse, Wedge, and Newman projections of Ethane's eclipsed conformation viewed along the C1-C2 axis.

Answer 1

Eclipsed form of any molecule is less stable than that of staggered form due to a lot of angle strain , we are asked for energies of eclipsed forms here. This question is explained on the basis of given data as follows:

Associated Energy 4 kJ/mol Sol- We are given, - Type of Strain Interaction Edipsing of a pair of t's Eclipsing of a H & a CH3 group Eclipsing of a pair of Chs groups Gauche (60) Interaction b/w CH₃ gps 6 kJ/mol zgot 11 kJ/mol 3.8 kJ/mol Other on two datas are for CH₂ &H or CH₂ & CH3 interactions cyclohexane chair; which we don't need as are asked for ethane's eclipsod conformation Се (i) Ethane's Sawhorse projection CH-CH₂) Rear C HAM H (Eclipsed) H fronte ( staggered) In eclipsed Sawhorse are total theclipsing of Look at the colours of indicate eclipsing Pherefore, energy of projection, we see that there pairs of it's circles around t's. Some colours It's. strain interaction here = 3 x 4 K Jl mol = 12 KJ/mol

(1) Chane's Wedge Projection. In co Wedge projechia - two of the valen consti- tuents remain on the plane of paper of other two above & below the plane of paper. Here, we consider c. bed be the central carbon such that - . e that the 3H-c-CH3 A Although, it is having very less strain as it is an ideal tetrahedral structure; but as per the data, we are given the following thens of strains can be found here - CH 1) Phoe CH₂-H interactions. = 3x6 = 18 K J lind 2) Three H-H interactions .=3x4 = 12 KJ/mol. - 30 Rumot Neoman on Lili) Ethane's heart KH 2 Fronte HT Staggered) (Eclipsed) As we can see that there are are eclipsing. There is no other three pairs of H's which strain a present here Otable. Therefore, total strain / interactions = 3x4 kJ/mol = 12 KJ/mol