Question

The chemical environment of carbons can be deduced form their chemical shifts. Deduce the relative chemical shifts of the carbons at the labeled positions. (Carbons that are highly shielded have low delta, chemical shift, values.) 1) The carbon with the smallest delta value (the most shielded) is . The carbon with the largest delta value (the most deshielded) is a

Answer 1

Part 1: The most shielded is c while the least shielded is a.

Part 2: The most shielded is b while the least shielded is a.

Step-by-step explanation:

As the complete question is not given than the reference question as viewed online is solved and is attached for reference.

Part 1:

The carbon of
`CH_3` is most shielded as it is most electronically rich so the answer for most shielded carbon atom is c.

The carbon of carbonyl group is least shielded as Oxygen is the electronegative radical so the answer for most shielded carbon atom is a.

Part 2:

The carbon of
`CH_3` is most shielded as it is most electronically rich so the answer for most shielded carbon atom is b.

The carbon of ring is least shielded as due to presence of the pi electrons so the answer for most shielded carbon atom is a.