25. Which of the following carbonyl groups exhibits the highest wavenumber in infrared spectroscopy? (A) (B) (C) (D) (E)

30. Using a 300 MHz 1 H NMR instrument, if a H shows a triplet at δ 4.02, 4.00, 3.98 ppm, please calculate it’s coupling constant. And where will this triplet peak shows up at a 600 MHz 1 H NMR instrument? (A) 6 Hz; δ: 4.01, 4.00, 3.99 ppm (B) 6 Hz;δ: 4.02, 4.00, 3.98 ppm (C) 6 Hz; δ: δ: 4.00, 3.98, 3.96 ppm (D) 2 Hz; δ: 4.02, 4.00, 3.98 ppm (E) 2 Hz; δ: 4.00, 3.98, 3.96 ppm.