Kemija - 2012./13. ljeto - 20.

A. ${\mathrm{H}\mathrm{S}\mathrm{O}}_3{}^{-}\backslash mathrm\{HSO\}\_\{3\}\{\; \}^\{-\}$

B. ${\mathrm{S}\mathrm{O}}_3{}^{2-}\backslash mathrm\{SO\}\_\{3\}\{\; \}^\{2-\}$

C. ${\mathrm{H}}_2{\mathrm{S}\mathrm{O}}_3\backslash mathrm\{H\}\_\{2\}\; \backslash mathrm\{SO\}\_\{3\}$

D. ${\mathrm{H}}_3{\mathrm{O}}^{+}\backslash mathrm\{H\}\_\{3\}\; \backslash mathrm\{O\}^\{+\}$