HCOOH\mathrm{HCOOH}HCOOH
CH3COOH\mathrm{CH}_{3} \mathrm{COOH}CH3COOH
C2H5COOH\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{COOH}C2H5COOH
C3H7COOH\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{COOH}C3H7COOH