Time for some chemistry!
Acids and Bases can be classified by 3 different defintions
1. Arrhenius Acids and Bases: An Arrhenius acid in water will increase the [H+] concentration. An Arrhenius base will increase the hydroxide [OH-] concentration.
2. Bronsted/Lowry: An acid will donate a proton while a base will accept a proton.
3. Lewis Acids/Bases: A Lewis acid (electrophile) will accept an electron while a Lewis Base (neutrophile) will donate an electron. Usually, a Lewis acid has a positive charge or an empty orbial (such as BF3). Transition metals like Fe3+ are also Lewis acids because of their positive charge. Lewis bases want to become neutral so they have negative charges due to carrying extra electrons.
A compound can be classified as a strong acid or base if it dissociates 100% in water
Strong Acids: HNO3, HCl, HBr, HI, H2SO4, HCLO4, HCLO3
Strong Bases: LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
Water is unique in that it is amphoteric. It can act as either an acid or a base
The strength of an acid or base is defined in 2 ways. Its pH/pOH, and its pKa/pKb.
pH = -log[H+], pOH = -log[OH-]. pH is on a scale from 0-14 with 0 being extremely acidic and 14 being extremely basic. Depending on the concenrations, numbers can be below 0 (negative) or above 14.
Pure H20 will ionize completely. H20 -> H+ + OH-
Writing out the Keq equation, Keq = Kw = [H+][OH-] = 10^-14, meaning H and OH have values of 10^-7. THIS IS ONLY VALID AT 25 degrees C. If the temperature is raised, there is a large amount of H+ and OH-. Looking at equilibrium stresses, a shift to the products side means that the reaction is endothermic.
For example, if the new Kw = 10^-12, H+ and OH- are equal to 10^-6 (which is a much higher concentration than 10^-7. The -log(10^-6) = pH = 6. The new neutral pH at that higher temperature is equal to 6.
