15.The 1H nmr spectrum of acetone consists of a singlet with a chemical shift of 2.07 ppm. What was the spectrometer frequency of the instrument used if this chemical shift equaled 186Hz? (A)60MHz (B)90MHz (C)100MHz (D)120MHz (E)Need more information to determine

13.Consider the following statements concerning the effect of a trifluromethyl group-CF3, on an electrophilic aromatic substitution. Which of these statements is (or are) correct? 1.The CF3 group will activate the ring. 2.The CF3 group will deactivate the ring. 3.The CF3 group will be a meta director. 4.The CF3 group will be an ortho, para director. (A)1,3 (B)1,4 (C)2,3 (D)2,4 (E)3,4

15.The ¹H nmr spectrum of acetone consists of a singlet with a chemical shift of 2.07 ppm. What was the spectrometer frequency of the instrument used if this chemical shift equaled 186Hz?
(A)60MHz
(B)90MHz
(C)100MHz
(D)120MHz
(E)Need more information to determine

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