Microscopic world ii

我見過一條A-LEVEL QUESTION,as follow

Explain HI has higher boiling point than HBr

答案話:HI has greater number of eletrons,so the boiling point of HI is higher.

不過我本書冇講過,所以我用molecular size 解釋,is it ok?

2 個解答

  • fooks
    Lv 7
    8 年前

    It is a correct answer that HI gas a larger molecular size than HBrleads to HI has stronger van der Waals' forces between molecules.

    資料來源: fooks
  • This is to do with the intermolecular forces in the two compounds. There are no hydrogen bonds between the molecules of either compound, since Br and I are not electronegative enough to polarise the molecules sufficiently. But since HI molecules contain more electrons than HBr, there are increased van der Waals forces in HI. For the same reason HBr has a higher boiling point than HCl, but HF has a higher boiling point than HCl, HBr or HI because of hydrogen bonding.