Question

The incorrect statement regarding conformations of ethane is:

• A. Ethane has infinite number of conformations
• B. The dihedral angle in staggered conformation is \(60\degree\)
• C. Eclipsed conformation is the most stable conformation.
• D. The conformations of ethane are inter convertible to one-another.

Answer 1

The Correct Option is C

To determine the incorrect statement regarding the conformations of ethane, let's evaluate the given options based on our knowledge of chemistry and molecular conformation: 

1. The statement "Ethane has infinite number of conformations" is correct. Ethane can rotate around the carbon-carbon sigma bond, and because this rotation can occur to any angular degree, it results in an infinite number of possible conformations.
2. The statement "The dihedral angle in staggered conformation is \(60\degree\)" is incorrect. In a staggered conformation, the dihedral angle is actually \(180\degree\). However, the common representation of one complete rotation typically uses the dihedral angles of \(60\degree\), \(120\degree\), etc., between hydrogen atoms on one carbon and those on the adjacent carbon.
3. The statement "Eclipsed conformation is the most stable conformation" is incorrect. The staggered conformation is actually the most stable conformation due to minimized repulsion between the hydrogen atoms bonded to the carbon atoms, making it lower in energy compared to the eclipsed form.
4. The statement "The conformations of ethane are inter convertible to one-another" is correct. Ethane can easily convert from one conformation to another through simple rotation around its carbon-carbon bond.

From the evaluation of each option, the incorrect statement is "Eclipsed conformation is the most stable conformation". Staggered conformation is more stable than the eclipsed conformation due to the torsional strain present in the eclipsed state.

Answer 2

Eclipsed conformation is the least stable conformation of ethane due to repulsion between electron clouds of adjacent C-H bonds. The staggered conformation is more stable.
The Correct answer is: Eclipsed conformation is the most stable conformation.