Acid/Base Arrhenius definition acid produces H + in water baseproduces OH - in water HA K a = [H + ] [A - ] [HA] [H 2 O] KaKa strength of acid strong acids dissociate completely no K a HCl, HNO 3, weak acids equilibrium process HF + H 2 O  H+H+ + A - [HA]  HBr,HI HClO 4,H 2 SO 4  K a = 6.8 x HIO 3 K a = 0.16

Acid/Base Arrhenius definition acid produces H + in water baseproduces OH - in water strong bases O 2- OH - Group I Group II (Ca, Sr, Ba) weak bases NH 3 R-NH 2 NaOH (s)+ H 2 O  Na + (aq) NH 3 (g)+ H 2 O  NH 4 + (aq)+ OH - (aq) KbKb amines K b = 1.8 x 10 -5

Autoionization of H 2 O H2OH2O  H + (aq) + OH - (aq) K w = [H+][H+][OH - ] [H 2 O] = 1.0 x at 25 o C 55.5 M Le Chatelier add H + [OH - ] decrease 0.10 mol HCl 1.0 L = 0.1 mol H + L [H + ] = 0.10 M [H+][H+]= [OH - ]= 1.0 x K w = [0.1][OH - ] = 1.0 x [OH - ] = 1.0 x both present in all aqueous solutions HH 0 >

pH [H+][H+]10 M M pH =- log[H + ] pH15low acidic high pH basic [H + ] = [OH - ] = 1.0 x pH = 7neutral pOH =- log[OH - ] pH+ pOH= 14 pHof milk= 6.4[H + ] = x sig. fig. 4 x 10 -7

Brønsted-Lowry Acids and Bases acidproton donor base proton acceptor H Cl + O H H..  Cl O H H H + acid base acid base conjugate pair very weak strong H.. stronger acid + stronger base

Brønsted-Lowry Acids and Bases acidproton donor base proton acceptor N H H H.. + O H H  N H H H H + + OH - base acid base weak baserelatively strong acid K b = 1.8 x 10 -5

Brønsted-Lowry Acids and Bases acidproton donor base proton acceptor + C 2 H 3 OOH CN -  C 2 H 3 OO - +HCN acid base 1 base acid 2 12

Brønsted-Lowry Acids and Bases acidproton donor base proton acceptor HF+H2OH2O  F-F- + H3O+H3O+ acid 1 base 1 base 2 acid 2 H3O+H3O+ strongest acid in water CH 3 NH 2 + H2OH2O  CH 3 NH OH - base 1 acid 2 acid 1 base 2 OH - strongest base in water amphoteric acid or base H2OH2O K a = 7.2 x 10 -4