Definitions acid & base
Definition according to Brønsted:
any substance that can donate H+-ions
any substance that can accept H+-ions
Definition according to Lewis:
any substance that can suffer increase of, has room for free electron pairs.
or: a structure that suffers lack of (free) electron pairs.
any substance that contains (more than) enough free electron pairs, and that can put available those pairs.
Starting with the following data, you can explain why teeths are more resistant against acids after treatment with fluor(ide).
the data are:
- the main components of bone in teeths is hydroxy-apatite:
- an ion OH- can easily been substituted by an ion F- (charge and size are more or less the same.).
That's how is made the substance fluor-apatite:
- The optimal percentage of OH- in apatite is 2%
- Tap water can be fluoridised with NaF
- F- is a weaker base than OH-