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Discuss anomalous behaviour of fluorine. |
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Answer» Solution :Fluorine shows anomalous behaviour due to : (i) Small size (ii) High ionisation enthalpy (iii) Absence of d-orbitals in valance shell (IV) High positive electrode potential Fluorine shows (-1) oxidation state only while other elements show (+1), (+3) (+5) and (+7) oxidation states. HF is liquid due to H-bonding while HCl, HBr and HI are gaseous in state. Fluorine does not FORM poly fluorides, FOREXAMPLE : `F_3` is not known. This is due to absence of d-orbitals in valance shell.Fluorine forms only one oxoacid (HOF) while other halogens form number of OXOACIDS. The maximum covalency of fluorine is one due to absence of d-orbital in valance shell while other halogens show covalence of 7. Hydrofluoric ACID is a dibasic acid (`H_2F_2`) while other hydrohalic acids are monobasic. `F_2` is highly reactive due to low bond (F - F) dissociation enthalpy. Fluorine forms hexafluoride (`SF_6`) while other halogens do not form hexahalides with sulphur. |
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