Spectroscopic analysis:

 The existence of an aromatic ring can be pointed out by IR, nmr and mass spectroscopy.

In the IR spectrum, the stretching absorption of an Ar-H bond takes place at 3040-3010 cm^-1 that is higher than the range for an aliphatic C-H stretch (3000-2800 cm^-1). Though, the absorption is generally weak and may be hidden. Absorptions because of ring vibrations are more reliable and can account for up to four absorptions (generally about 1600, 1580, 1500 and 1450 cm^-1). These take place at lower wavenumbers to the C=C stretching absorptions of alkenes (1680- 1620 cm^-1). Ar-H out of plane bending can provide absorptions in the area 860-680 cm^-1. The number and position of these absorptions can point out the substitution pattern of the aromatic ring. For instance, an ortho disubstituted ring generally has absorption at 770-735 cm-¹ while a para disubstituted ring has an absorption in the region 860-800 cm^-1. A monosubstituted aromatic ring comprises two absorptions in the regions 690-710 and 730-770 cm^-1 whereas a meta-disubstituted aromatic ring has two absorptions in the regions 690-710 and 810-850 cm^-1. These bending absorptions are not all the time reliable and may be difficult to differentiate from other absorptions in the region.