According to the Arrhenius theory, the only negative ions in an aqueous solution of a base are

According to the Arrhenius theory, the only negative ions in an aqueous solution of a base are

• A. HS- ions
• B. H- ions
• C. HCO3- ions
• D. OH- ions

Answer: (D)

In Arrhenius terms, a base increases the hydroxide ion concentration in water by dissociating to produce OH-. When a base dissolves, the negative ion tied to its basic behavior is the hydroxide ion, so OH− is the only negative ion formed directly by the base in solution. The other species listed would not arise from the base’s dissociation in this model (they would require different reagents or subsequent reactions in water). Thus, the hydroxide ion is the negative ion present due to the base in aqueous solution.

In Arrhenius terms, a base increases the hydroxide ion concentration in water by dissociating to produce OH-. When a base dissolves, the negative ion tied to its basic behavior is the hydroxide ion, so OH− is the only negative ion formed directly by the base in solution. The other species listed would not arise from the base’s dissociation in this model (they would require different reagents or subsequent reactions in water). Thus, the hydroxide ion is the negative ion present due to the base in aqueous solution.