题干

已知氨水与醋酸的电离程度在同温同浓度下相等,溶有一定量氨的氯化铵溶液呈碱性.现向少量的Mg(OH)2悬浊液中加入适量的饱和氯化铵溶液,固体完全溶解.

甲同学的解释是:

Mg(OH)2(s)⇌Mg2+(aq)+2OH‑(ap)①

NH 4+ +H2O⇌NH3•H2O+H+②

由于NH 4+ 水解显酸性,H+与OH﹣反应生成水,导致①导致的平衡右移,沉淀溶解;

乙同学的解释是:

Mg(OH)2(s)⇌Mg2+(aq)+2OH‑(ap)①

NH 4+ +OH﹣⇌NH3•H2O②

由于NH4Cl电离出的NH 4+ 与Mg(OH)2电离出的OH﹣结合,生成了弱电解质NH3•H2O,导致反应①的平衡右移,Mg(OH)2沉淀溶解.

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