Answer
The more stable chair is the first one.
** If we start counting from the top carbon on the hexagon, the top right carbon on the first chair, and the bottom right carbon on the second chair.
** Your drawing can be different, but the more stable drawing has to have 2 equatorial methyls.
Work Step by Step
1. Draw both chairs with the substituents.
- We've learned how to do this on the previous sections.
** For this drawing, we start counting the carbons by the top carbon on the hexagon, the top right carbon on the first chair, and the bottom right carbon on the second chair.
2. Find the largest substituent.
- In this case all substituents are methyls, so the more stable chair will be the one where most methyls are equatorials.
3. Now, identify the chair where the largest group is in the equatorial position.
- The first chair has 2 equatorial methyl groups, so it is the more stable.
