According to Arrhenius theory, when a base is dissolved in water it produces a solution containing only one kind of negative ion. Which ion is referred to?

According to Arrhenius theory, when a base is dissolved in water it produces a solution containing only one kind of negative ion. Which ion is referred to?

• A. Hydroxide
• B. Hydrogen
• C. Hydride
• D. Hydronium

Answer: (A)

In Arrhenius terms, a base dissolves in water to produce hydroxide ions (OH−) in solution. The negative ion present is the hydroxide ion, which is why bases raise the concentration of OH− in the liquid. For example, dissolving a strong base like NaOH gives Na+ and OH−. The other options don’t fit: the hydrogen ion (H+) is a positive charge, not a negative ion; hydride (H−) isn’t formed in typical aqueous base solutions; and hydronium (H3O+) is the positively charged form that dominates in acidic solutions, not when a base is dissolved.

In Arrhenius terms, a base dissolves in water to produce hydroxide ions (OH−) in solution. The negative ion present is the hydroxide ion, which is why bases raise the concentration of OH− in the liquid. For example, dissolving a strong base like NaOH gives Na+ and OH−. The other options don’t fit: the hydrogen ion (H+) is a positive charge, not a negative ion; hydride (H−) isn’t formed in typical aqueous base solutions; and hydronium (H3O+) is the positively charged form that dominates in acidic solutions, not when a base is dissolved.