Question

please help with 6A and 9. thank you!

Usech occurs at about 1640 cm-1. C) here is no change in the dipole moment when the CC bond in the molecule stretches. D) there is a change in the dipole moment when the CC bond in the molecule stretches. 9. Which of the following compounds has the lowest carbonyl stretching frequency? (2 pts) 0 CH3 8 do do con congue 10. is commonly used as an internal reference in NMR spectroscopy; its sign chemical shift, 8 = 0 in 1H (and 13C NMR) spectroscopy. (2 pts) Tetramethylsilane (TMS)

Answer 1

28 30 to 80 Here, only compound ④, the conjugation present. hu so, Here, the cao bond get to partially single bund character, so the carbonyl stretching frequency decrease. On the another compound ® , and such Conjugation not present. So there cao stretching frequency not decrease. : carbonyl so, o this compound has lowest a stretching frequency 6. @ Termin - Terminal alkynes will show a prominent peak at about 3300 cm' for sp-hybridized e-H. as, ② x intense IR absorption at this componend 3300 ml.