Kemija - 2011./12. ljeto - 35.

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

B. ${\mathrm{H}}_2\mathrm{O}\backslash mathrm\{H\}\_\{2\}\; \backslash mathrm\{O\}$

C. ${\mathrm{C}\mathrm{O}}_3{}^{2-}\backslash mathrm\{CO\}\_\{3\}\{\; \}^\{2-\}$

D. ${\mathrm{H}\mathrm{C}\mathrm{O}}_3{}^{-}\backslash mathrm\{HCO\}\_\{3\}\{\; \}^\{-\}$