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What is hydrogen bond ? Explain its characteristics with example. |
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Answer» Solution :Attraction force present between partially positive `n^(+)` ion and partially negative molecules like N - H, O - H or H - F is Known as HYDROGEN Bond. Example :(i) N - H of `NH_(3)`, (ii) O - H of `H_(2)O, C_(2)H_(5)OH, C_(6)H_(5)OH`(iii) H - F of H - F,(iv) O - chloro phenol formation of H - Bond in H - F. `overset(delta+)(H)-overset(delta-)(F).....overset(delta+)(H)-overset(delta-)(F)` Characteristics : Although hydrogen bonding is regarded as being limited to N, O, F , but species such as `Cl^(-)` may also participate in hydrogen bonding. ENERGY of hydrogen bond varies between 10 to 100 KJ `mol^(-1)`. This is quite a significant amount of energy , therefore hydrogen bonds are powerful force in determining the STRUCTURE and properties of many compounds, for example proteins and nucleic acids. Strength of the H-bond is determined by coulombic interaction between the lone pair electrons of the electronegative atom of one molecule and the hydrogen atom of other molecule. Energy of hydrogen Bond varies between 10 to 100 kJ `mol^(-1)` This is quite a significant amount of energy , therefore, hydrogen bonds are powerful force in determining the structure and properties of many compounds, for example proteins and nucleic acids. Distance between molecules in same substance increases, strength of H - Bond decreases. ex. : Solid `to` Liquid `to` Gas |
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