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对在含有Mg~(2+)、Al~(3+)的溶液中加入强碱或强碱弱酸盐的溶液发生化学反应的描述在不少中学化学资料中出现了误导,就此特作如下分析: 一、在Mg~(2+)、Al~(3+)的混合溶液中加入NaOH溶液时是否同时生成氢氧化物的沉淀。现行的不少资料中,只要是涉及向含有Mg~(2+)、Al~(3+)的混合溶液中持续加入NaOH溶液,都认为是同时产生Mg(OH)_2和Al(OH)_3的沉淀,当碱过量时,Al(OH)_3溶解,并把此过程用曲线表示如下:
A description of the chemical reaction of a solution containing a strong base or a strong base weak acid salt in a solution containing Mg ~ (2 +) and Al ~ (3+) appears to be misleading in many middle school chemical data and is hereby made as follows Analysis: First, in the Mg ~ (2 +), Al ~ (3 +) mixed solution of NaOH solution is added at the same time whether the precipitation of hydroxides. It is considered that the simultaneous generation of Mg (OH) _2 and Al (OH) _3, as long as it involves the continuous addition of NaOH solution to the mixed solution containing Mg2 + and Al3+, Of the precipitate, when the base is excessive, Al (OH) _3 dissolved, and the process curve as follows: