Question

Determine the unsaturation number (UN#) for the unknown compounds using the molecular formula. Determine the functional groups present in the IR spectrum

Determine the final structure of the unknown

Spectra Set #5 C8H10 & 8 R S 2925 8 Transmittance 8 3032 8 note that the aromatic C-H stretches are to the left of 3000, and the alkyl C-H stretches are to the right of 3000 0 4000 2000 Wavenumbers (cm-1) 7 6 5 PPM

Answer 1

Molecular formula = C8H10

Degree of unsaturation = (2C+2+N-X-H) / 2

Degree of unsaturation = (2*8+2-10)/2

Degree of unsaturation = 4 (presence of benzene ring)

IR data

2925 cm-1 Presence of aliphatic C-H stretch

1614cm-1 C=C stretch

1H NMR data

7.01-7.30 (m, 5H)

2.6 (q, 2H) CH2 group attached to benzene ring and CH3

1.25 (t, 3H) CH3 group attached to CH2

All above data indicates following structure

ethylbenzene Chemical Formula: CgH10