题目：
下列叙述中不正确的是
A．Na、NaCl、SiO2的熔点逐渐升高
B．1 mol乙醛与足量新制的银氨溶液反应生成1 mol Ag
C．一定条件下可将干冰转化或组成为“CO2"的原子晶体，该晶体中每个碳原子与四个氧原子结合
D．工业上通常用电解熔融MgCl2的方法冶炼Mg
答案：
答案：B
本题考查晶体的性质。SiO2是原子晶体，熔点最高，A正确；根据关系：－CHO～2Ag，所以B错误；根据原子晶体的结构得出C正确；MgCl2是离子化合物，且熔点低于MgO，所以D正确。
下列叙述中不正确的是 A．Na、NaCl、SiO2的熔点逐渐升高 B．1 mol
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