Question

In the Newman projection for 2,2-dimethylbutane, X and Y can respectively be:

This questions has multiple correct options
A. H and H
B. H and ${C_2}{H_5}$
C. ${C_2}{H_5}$ and H
D. $C{H_3}$ and $C{H_3}$

Answer 1

We have to know that a Newman projection is helpful in studying the alkane stereochemistry for picturing the conformation of a chemical bond from front to back.

Complete step by step answer:
In the stereochemistry of alkane, Newman projection is very helpful. We can visualize the conformation of a chemical bond from front to back. We can use a dot to indicate the front carbon atom, and a circle to represent the back carbon atom.
Proximal is the term given to the front carbon atom, and the distal is the term given to the back carbon atom.
From the name 2,2-dimethylbutane, we can understand that the parent carbon chain is butane and two methyl groups are substituted at the carbon second position in the parent carbon chain that is butane. We can draw the structural formula of 2,2-dimethylbutane as,

Using the ${C_1} - {C_2}$ bond, we can draw the Newman projection as,

Using the ${C_3} - {C_2}$ bond, we can draw the Newman projection as,

So using ${C_1} - {C_2}$ bond, the substituent on the X is $H$ and the substituent on the Y is ${C_2}{H_5}$.
So using ${C_3} - {C_2}$ bond, the substituent on the X is $C{H_3}$ and the substituent on the Y is $C{H_3}$.
The specific dihedral apple between the proximal and distal atom is illustrated by Newman representation. Newman projection is an alternative to sawhorse projection.

Thus, Options (B) and (D) are correct .

Note:
We can use Newman projection to visualize any kind of bond, not a single bond present between carbons of an alkane. For example, we can use it to study cyclic molecules like the chair conformation of cyclohexane.