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The boiling points of HCl HBr and HI increase
问题详情
The boiling points of HCl，HBr and HI increase with increasing molecular weight. Yet the melting and boiling points of the sodium halides，NaCl，NaBr，and NaI，decrease with increasing formula weight. Explain why the trends opposite.
参考答案
HCl，HBr and HI are alI molecular crystals. There is a force in moleeulars. The boiling points of HCl，HBr and HI increase with increasing molecular weight because the force in moleculars increase with increasing molecular weight.
The melting and boiling points of the sodium halides，NaCl，NaBr，and NaI，decrease with increasing formula weight，because the ionicity of NaCl，NaBr，and NaI decrease with increasing formula weight.
