Identify which compound this unknown is from this list, please explain.

1) benzaldehyde

2) bromobenzene

3) 1-butanol

4)m-cresol

5) cyclohexanone

6) cyclohexane

7) n-dibutylamine

8) 3,7-dimethyl-1-octanol

9) isoamyl acetate

10) isoamyl alcohol

11) methyl benzonate

12) 3-methyl-3-pentanol

13) 4-methyl-2-pentanone

14) 3-pentanone

15) 1-pentene

16) phenetole

17) toluene

18) o-toluidine

19) valeraldehyde

20) vinyl acetate