Question

Decreasing the electron density around a nucleus deshields it, causing the chemical shift to increase and moving the signal to the _____, resulting in a(n) ________ shift.

A) Left, Upfield
B) Right, Downfield
C) Left, Downfield
D) Right, Upfield

Answer 1

Decreasing electron density around a nucleus leads to a less deshielded nucleus and an increased chemical shift in NMR spectroscopy, causing the signal to move to the right or downfield, corresponding to answer B) Right, Downfield.

Step-by-step explanation:

The question is asking about the effect of decreasing electron density around a nucleus on the chemical shift observed in nuclear magnetic resonance (NMR) spectroscopy. When the electron density around a nucleus is decreased, the nucleus is less deshielded, which leads to an increase in the chemical shift. As a result, the signal is moved to the right on an NMR spectrum, which is referred to as a downfield shift. Therefore, the correct answer is B) Right, Downfield.