Acids and Bases

Outline Acidic and Basic Solutions Neutral Solution Arrhenius Model Bronsted-Lowry Model Amphoteric and Polyprotic Strength of Acids and Bases Neutralization Reaction Titration

Acidic and Basic Solutions Acidic Solution – Contains more hydrogen ions than hydroxide ions Turn blue litmus red, tastes sour, has a pH of less than 7, and reacts with active metals, carbonates, and bases. The closer to 1, the more acidic.

Acidic and Basic Solutions Basic Solution – Contains more hydroxide ions than hydrogen ions Turns red litmus blue, tastes bitter, feels soapy or slippery, has a pH of greater than 7, and reacts with acids. The closer to 14 the more basic.

Neutral Solutions Neutral Solution – Contains equal number of hydroxide ions and hydrogen ions. Has a pH of 7. Water is a good example

Arrhenius Model Acids contain hydrogen and ionize to produce hydrogen ions in aqueous solutions Bases contain hydroxide groups and dissociate to produce hydroxide ions in aqueous solutions

Bronsted-Lowry Model Acid is a hydrogen ion donor. Creates a conjugate base. Base is a hydrogen ion acceptor. Creates a conjugate acid. Works in any solvent

Bronsted-Lowry Model Cont. Conjugate Acid – substance produced when a base accepts a hydrogen ion. Conjugate Base – substance produced when an acid donates a hydrogen ion.

Amphoteric and Polyprotic Acid Amphoteric – Substance that can act as both an acid and a base such as water. Polyprotic Acid – An acid that can donate more than one hydrogen ion. Two is diprotic Three is triprotic

Strength of Acids and Bases Strong Acids/Bases – ones that completely ionize Includes HCl, HNO3 Weak Acids/Bases – Only partially ionizes in dilute aqueous solutions. Includes HF, Acetic, H2S Every change in pH is a factor of ten in hydrogen ion concentration. The smaller the number, the higher the concentration. pH of 1 has 1000 times more hydrogen ions than a pH of 4. pH of 12 has 100 times less hydrogen ions than a pH of 10.

Neutralization Reaction When an acid and a base react in an aqueous solution (water) to produce a salt and water Salt – ionic compound with the cation from the base, and the anion from the acid HCl + NaOH -> NaCl, a salt, + H2O

Titration Reacting a known concentration of solution with an unknown concentration of solution Equivalence Point – when moles of H+ equal moles of OH- End Point – Indicator in titration changes color indicating equivalence point Stop sign