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 the Isopropyl group on an equatorial position.
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, it is the Isopropyl (i-Pr).
3. Now, identify the chair where the largest group is in the equatorial position.
- In the first chair, the Isopropyl is on an equatorial position, so it is the more stable.