結論：

鹼是離子化合物，在固體狀態下仍含有離子，但這些離子之間具有強烈的吸引力。只有在溶液中，這些離子才能夠自由游動。下面列舉了幾種常見鹼溶液的離解反應式：

• \(\text{NaOH}\left( \text{s} \right)\ \text{+}\ {{\text{H}}_{\text{2}}}\text{O}\left( \text{l} \right)\ \to \ \text{N}{{\text{a}}^{\text{+}}}\left( \text{aq} \right)\ \text{+}\ \text{O}{{\text{H}}^{-}}\left( \text{aq} \right)\)
• \(\text{Ca}{{\left( \text{OH} \right)}_{2}}\left( \text{s} \right)\ \text{+}\ {{\text{H}}_{\text{2}}}\text{O}\left( \text{l} \right)\ \to \ \text{C}{{\text{a}}^{\text{2+}}}\left( \text{aq} \right)\ \text{+}\ 2\text{O}{{\text{H}}^{-}}\left( \text{aq} \right)\)
• \(\text{N}{{\text{H}}_{\text{3}}}\left( \text{g} \right)\ \text{+}\ {{\text{H}}_{\text{2}}}\text{O}\left( \text{l} \right)\ \to \ \text{N}{{\text{H}}_{\text{3}}}\left( \text{aq} \right)\)
  \(\text{N}{{\text{H}}_{\text{3}}}\left( \text{aq} \right)\ \text{+}\ {{\text{H}}_{\text{2}}}\text{O}\left( \text{l} \right)\ \rightleftharpoons \ \text{N}{{\text{H}}_{\text{4}}}^{\text{+}}\left( \text{aq} \right)\ \text{+}\ \text{O}{{\text{H}}^{-}}\left( \text{aq} \right)\)

可以看出：鹼溶液中存在唯一一種陰離子——氫氧離子（\(\text{O}{{\text{H}}^{-}}\left( \text{aq} \right)\)）