A few questions about pH?

Question

1.what is the relationship between disassociation and the concept of acids and basics?

2.how does the pH scale work?

3. exactly define the number of hydrogen and hydroxide ions at pH 6.

Answer 1

Sure, I'll help you with your homework.

1) Higher disassociation of acid = more acidic

2) pH= - (log H)

3) 10^ -6 H+ per liter and 10^ -8 OH-

Answer 2

1.  It is "dissociation", not dis-association".  Many substances dissociate or break apart into ions when dissolving in water.  Most of the substances tend to have bonds with high ionic character or they have polar covalent bonds.  The strong acids dissociate completely into a hydrogen ion and some anion.  Weak acids don't dissociate completely, but stay as dissolved molecules.  Strong bases dissociate into a hydroxide ion and a cation.  Weak bases don't dissociate completely.

2.  The pH scale is a logarithmic scale that runs from between -1 and -2 to over 14.  (The 0 to 14 range is a holdover from analog pH meters.)  It is a measure of the concentration of hydrogen ions in solution and calcuated from this relationship:  pH = -log[H+].  Each 1 pH unit interval represents a change in hydrogen concentration by a factor of 10.

3.  The hydrogen ion concentration, [H+], is computed from this relationship:  [H+] = 10^-pH.  A pH of 6 means that the hydrogen ion concentration is 1 x 10^-6.  

The product of the hydrogen ion centration and the hydroxide ion concentration is Kw, or 1 x 10^-14 (at about 25C)

Kw = [H+] x [OH-]

Also, we can introduce pOH which is just like pH only different.  It deals with the concentration of OH-

Therefore

14 = pH + pOH

So pOH = 8

and [OH-] = 1 x 10^-8