Physical Chemistr Nonideal Systems Reaction equilibrium in electrolyte solutions Many ionic reactions in solution are acid-base reactions e Bronsted definition of acidbase Acid: a proton donor Base: a proton acceptor water: amphoteric, either a proton donor or a proton acceptor H,O+HO台H2O++OH (11.10) K°=∏ (11.6) K a(hOa(OH) [a(H2O)2 The standard state of the solvent H2O is pure H2O a(h,O) pure
6 Reaction Equilibrium in electrolyte solutions Many ionic reactions in solution are acid-base reactions. + − H2 O + H2 O H3 O + OH (11.10) Brønsted definition of acid/base Acid: a proton donor Base: a proton acceptor water: amphoteric, either a proton donor or a proton acceptor i i i eq o K a ( ) , (11.6)* 2 2 3 [ ( )] ( ) ( ) a H O a H O a OH K o w + − = (11.11) The standard state of the solvent H2O is pure H2O. a(H2 O) pure =1 Physical Chemistry Nonideal Systems
Physical Chemistr Nonideal Systems Reaction equilibrium in electrolyte solutions In aqueous solutions a(H,O)=r(HO)x(H,O) e for dilute aqueous solutions a(H2O)≈1,a1=ym1/m K=a(Ho a(oh) Lr(H3O)m(H3o)/mr(oh )m(OH)/m] Omission of the solvent's activi For the ho ionization V+=l=V, 2+=rr Kp=rim(Hgo )m(OH)/(m) dilute aqueous solution(11. 12yo
7 Reaction Equilibrium in electrolyte solutions In aqueous solutions [ ( ) ( )/ ][ ( ) ( )/ ] ( ) ( ) 3 3 3 o o o w H O m H O m OH m OH m K a H O a OH + + − − + − = = For the H2O ionization Omission of the solvent’s activity. ( ) ( ) ( ) a H2 O = x H2 O x H2 O For dilute aqueous solutions o a(H2 O) 1,ai = i mi / m (11.12)* 2 3 2 ( ) ( )/( ) o o Kw m H O m OH m + − = dilute aqueous solution + = = − = + − 2 1 , Physical Chemistry Nonideal Systems
Physical Chemistr Nonideal Systems Reaction equilibrium in electrolyte solutions For the ionization of the weak acid hX in aqueous solution Hx+H2O分HO++X K r(HO)m(HO)/mlr(x)m(X )/m (11.14 y(HX)m(H/m° In dilute solution m(hO)m(X dilute solution 11.15) m(Hr) The pair of ions HO/X-
8 Reaction Equilibrium in electrolyte solutions For the ionization of the weak acid HX in aqueous solution + − HX + H2 O H3 O + X (11.13) o o o o a HX m HX m H O m H O m X m X m K ( ) ( )/ [ ( ) ( )/ ][ ( ) ( )/ ] 3 3 + + − − = (11.14) In dilute solution dilute solution (11.15) ( ) ( ) ( ) 3 2 m HX m H O m X Ka + − = The pair of ions H3O+/XPhysical Chemistry Nonideal Systems