C6H5−CH3−COOH\mathrm{C}_{6} \mathrm{H}_{5}-\mathrm{CH}_{3}-\mathrm{COOH}C6H5−CH3−COOH
C6H5−COOH\mathrm{C}_{6} \mathrm{H}_{5}-\mathrm{COOH}C6H5−COOH