制取银氨溶液异常实验现象的探究

Inquiry on Abnormal Phenomenon in Preparation of Silver Ammonia Solution

将市售硝酸银试剂配成溶液,滴入氨水,反应液始终保持澄清,初步认为这种异常实验现象是由硝酸银试剂中含有少量硝酸铵杂质引起的。测定了向硝酸银溶液中加入氨水生成氧化银沉淀的质量,指出制取银氨溶液时只有少部分硝酸银与氨水反应生成中间产物氧化银,大部分硝酸银与氨水反应直接生成银氨络合物。探析了向硝酸银溶液中滴入氨水,反应液始终澄清或生成白色沉淀的异常实验现象。

Silver nitrate solution was prepared by the commercially available reagents. It remained transparent while ammonia water was added dropwise, which was caused by the existence of trace impurity ammonium nitrate in the silver nitrate reagents. In the reaction of silver nitrate solution with ammonia water, the product mainly was silver ammonia complex, and a little mid-product silver oxide, by the mass determination of silver oxide precipitation in the reaction. Furthermore, the problem was also explained that the product was transparent solution or white precipitation while ammonia water being added dropwise into silver nitrate solution.