Monday, August 23, 2010

Words about acids, bases, and polarizing forces

The words "acid" and "base" are functional terms, and not labels.  They describe what a substance does, rather than what it is.
~R. von Handler
The quote comes from an undergraduate chemistry textbook.  I assume that von Handler was a German physical chemist, but I've been unable to find anything else about him or his work. Schade.

Von Handler is saying that nominal concepts like acid and base are better understood as the functional concepts acidity and basicity. Some things are better understood by what they do rather than what they are. So to get at what von Handler was trying to say, we just have to think about what acids and bases do and that's easy: they attract opposite polarity and they repel like polarity.  In the natural world acids and bases polarize other molecules using attractive and repulsive forces to hasten change. Back here I wrote:
How nature really works (at a chemical level) is polarization followed by attack followed by depolarization.
Wish I could explain it better because it really is a simple concept.


  1. Bacon was more concerned with thermodynamics which in chemistry deals with whether something can happen. Acids and bases are catalysts and deal more with catalysis and kinetics or in other words how and how fast things happen.

  2. Wow man. You've been blogging up a storm.

    I never figured out how you always retained so much fascination with general chemistry. You're right that these can be somewhat fundamental concepts in and of themselves, which is why I'm impressed at how you always seem to find a different angle through which to look at them, or perhaps reflect on them is the better way to put it.

    I guess that's why I didn't major in chemistry.

    I liked your Elvis post too.

  3. Thanks Ritmo. You're a tough audience.

  4. Well... I'll let you in on a little secret. I always thought you were a good guy and respected the rigor you put into your thoughts. We obviously share an interest in science and life's too short to get bogged downed by the silly things that your masthead rightly refers to as loco.

    Science is a good way to learn how to appreciate both rules and creativity.

    As far as being tough goes, I'm working on it. ;-) Recognizing a distinction between the harmless, intentional silliness that everyone needs and the more serious stuff is probably the right start, as is a sense of proportion.

    Cheers -

  5. I can understand how 'acid' might attract opposite polarity, and consider things like chicken (crazy or otherwise) as being opposite and polarizing all of it quickly - I assume this is what makes acid eat stuff away. But how does a base operate if it also polarizes things and repels things with like polarity? I'm not disagreeing, I am sitting at the feet of the wise hoping for enlightenment...

  6. I'm going to try to answer my own question without the use of google. I figure that a base polarizes acids, right? So, it "pulls apart" acids and makes them base. This is why when I have heartburn and take some baking soda and water (nasty) it neutralizes it - polarizes it. Feel free to add...still sitting at the feet of wisdom here...

  7. Ritmo--go back to the Beach Boys thread-- I owe you one.

    Candle, I'm going to write you a response now.

  8. Here's what I mean: keep in mind the atomic model: a cloud of minus charge surrounds a tiny point of positive charge. When an acid, say H+ approaches an atom, it begins to attract the negative electronic cloud surrounding that atom. The H+ polarizes the atom's cloud and ever so-slightly exposes the atom's positive core. The exposed core (or nucleus), in turn becomes vulnerable to attack. An attacking entity (called a nucleophile) can be another atom that winds up bound to the first atom after an electron donation. After bond formation the acid falls away and the original atom(s) depolarize.

    Bases work by deprotonating acids (as you say). This is also a polarizing event event though opposite in "sign" to the acid. The base takes away positive charge and leaves behind a more negatively charged H+ donor. Bases can soup-up nucleophiles making them even more reactive. Hydroxyl OH- is more reactive than water.

    In other words, bases can make nucleophiles more aggressive; acids make electrophiles more receptive.

  9. Thanks, I get it now. But I'll forget again :( I have "intelophiles" in swimming in my head.

  10. Candle- it also helps to keep in mind that in water, molecules are surrounded by water molecules which mollify reactive because they (the water molecules) turn their oppositely charged parts towards any charged part of a molecule. Imagine a plus being surrounded by a sphere of waters. An acid or base can help unmask that layer of solvent goo and speed things up.

  11. You are not a polarizing force Candle.

  12. I never figured out how you always retained so much fascination with general chemistry.

    Ritmo, I had a couple few world class mentors. They infected me.