試題詳解

20. Using a 60 MHz spectrometer, a chemist observes the following absorption: doublet, J = 7.0 Hz, at δ 4.00. What would the chemical shift (δ) be in the 300 MHz spectrum?
(A) 3.50
(B) 4.00
(C) 4.50
(D) 20.0
(E) 0.80