Page 11 - E-LKM ASAM BASA
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Examples of Lewis Acid–Base Reactions
The reaction between BF and NH illustrates a Lewis acid–base
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neutralization. The reaction is exothermic because a bond is formed
between N and B, with the nitrogen donating an electron pair and the
boron accepting it.
The ammonia molecule thus acts as a Lewis base. The boron atom
in BF , having only six electrons in its valence shell and needing two
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more to achieve an octet, accepts the pair of electrons from the
ammonia molecule. Hence, BF is functioning as a Lewis acid.
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As this example illustrates, Lewis bases are substances that have
completed valence shells and unshared pairs of electrons (e.g., NH ,
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-
H O, and O ). A Lewis acid, on the other hand, can be a substance
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with an incomplete valence shell, such as BF or H .
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