Question

How many different staggered conformations are there for 2 -methylpropane? How many different eclipsed conformations are there?

Short answer

Answer: There are three distinct staggered conformations and three distinct eclipsed conformations for 2-methylpropane.

Step-by-step solution

Draw the structure of 2-methylpropane

Draw a structural diagram of 2-methylpropane (isobutane), which has a carbon atom bonded to three other carbon atoms, forming a branched structure. - Central carbon (C2) is bonded to a methyl group (CH3) and two other carbon atoms (C1 and C3). - C1 and C3 are each bonded to three hydrogen atoms forming terminal methyl groups. C1 | C3--C2--CH3 | C4

Identify the rotation axis for the Newman projection

The Newman projection will be viewed along the C2-C3 bond axis. This axis helps us to see the relative positions of the groups attached to C2 and C3.

Draw the Newman projection and determine staggered conformations

To draw the Newman projection, start with the front carbon (C2) and the groups attached to it. Rotate around the C2-C3 bond axis and count distinct staggered conformations by varying the relative positions of the groups attached to C2 and C3 such that they are as far apart as possible to minimize the steric strain. There are three distinct staggered conformations for 2-methylpropane: 1. C1 (attached to C2) anti to C4 (attached to C3) 2. CH3 (attached to C2) anti to C4 (attached to C3) 3. CH3 (attached to C2) anti to C1 (attached to C3)

Determine eclipsed conformations

Now, we need to determine how many different eclipsed conformations there are. Eclipsed conformations occur when the groups attached to C2 and C3 majorly overlap and are as close as possible, increasing the steric strain. There are three distinct eclipsed conformations for 2-methylpropane: 1. C1 (attached to C2) syn to C4 (attached to C3) 2. CH3 (attached to C2) syn to C4 (attached to C3) 3. CH3 (attached to C2) syn to C1 (attached to C3) In conclusion, there are three different staggered conformations and three different eclipsed conformations for 2-methylpropane.