InterviewSolution
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what is meant by H bond, why HF and H2O are liquid. whereas HCl, HBr, HC and H2S are gases |
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Answer» a weak bond between two molecules resulting from an electrostatic attraction between a proton in one molecule and an electronegative atom in the other. It would be worth specifying that hydrogen fluoride boils at about 20∘C, so if by room temperature you mean 25∘C, then hydrogen fluoride will actually be a gas. Impotant thing is that they havedifferent number of lone pairspresent on the more electronegative atom. In water's case, you have two partial positive hydrogen atoms andtwo lone pairsof electrons on the oxygen atom, which means that each water molecule can form hydrogen bonds withfourother water molecules. Hydrogen fluoride hasthree lone pairsof electrons, but only one hydrogen atom. This means that on average you will have insufficient partial positive hydrogen atoms to allow for the majority of hydrogen fluoride molecules to hydrogen bond at a particular moment. Both HCl and HF are gases at room temperature. But HF has high boiling point than HCl because of the reason that in HF the strength of hydrogen bond is stronger than the strength of hydrogen bond in HCl. |
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