Question

At 25° C the thermodynamic activity product (Kw) for the autopyrolysis of water 21,0 H,0+1 + OH-1 may be formulated as Ku= [H3O+][OH-] = 1.008x10-14 where [H3O+1] and [OH-] represent the activities of hydronium ion and hydroxide ion, respectively, and where the activity of water is taken to be unity. a) Using the Davies equation, the equilibrium expression and the definition of pH, show that pH = 6.998-(0.512 -0.2u 1+ Ju pH = 6.998–(0.512 -0.24 Davies equation -log7: = 0.51227 Davies equation – log 7+ = 0.512Z 24 - -0.24 0.2 1+ (Where pH=-log[H3O+1]) ZA= the charge on the anion Zc = the charge on the cation = the mean ionic strength Using the result of the preceding derivation, construct a plot of pH versus/(u) for potassium chloride solutions of the following concentration at 25 °C: 0,0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, and 2.0 M. How does the pH of an aqueous 2.00 M potassium chloride medium vary as the solution is extensively diluted with water? How could you best observe this variation in pH experimentally?

Answer 1

Ang @ Kw = 6430ty -) < 1.008x1014 - 142073 , X 107, lower LXTO Devises equation phs 6.998-20.572)/ -0.2m) 80 Me mean tonic strength. M = £ į cizie e cia moles concentration oflon Zürichonse of the lone Now for option A. pusmlog 430+). 3.A: 1 to b e Tsits ERHOZ 444 ) beroste pak 6998-to-525/ 070*707-02 M = £1 [230] *(+)2 + (04-) *(-1) 2 ans [1X/6-7x7 1210-7*1) : [exio-7) = X10-7 Nowe pH= 6.999.- cois 10-7 - 0.2%10 PH = 6:997) Ame e 6) PH = 4.998- (our (3 -o 2 ) Ct101 2) fog cedere concentration 0.0 I them to aso a pu = 6.998 Ta is comentration 0. 2M M=0,2 a 84 = 6.851 ce is concentreerios 0.4 m kce u= t[0.ux(+12+0.48 (42] = kt ce- E Oil then p = 6.89

CLEAN (7) is co= 0.6M -- --0-6 them-p466:6.B tes 0-BAA I htus 0. 8then p46.852 Page No. p" = G.Buy al is cc>= 1.0M L e = 1 then _ [21:24_ Rea 1.2 then pu = B.BUL rep if co = 1.4 M u-114 them p4 = 6.842 then pu = 6.646 if co = 1.6 M u = 1.6 it treten a = 11 them p4 - 6.653 16 [7=2.0M ce=2.0 then p4 = 6.861 phus ce for dissement - a concentreeson of kee... 00 6.2 0. 0.6 6.8 1.0 1.2 y i l 1.8 2.0 Date Teacher's Signature :

from this greeph we observed that aet o.on the ph is maximcem, but after when we increased concentration of Kel, the pu o of that solation in was a slightly decoelve and almost Remcem's Bo consetemt esp to pred some 2,0 M concentration. It means that d if we increase the concentration a is increased but the ph of this solution Remate almost constento on other woorde wonen meem jonic strength does not efseet on pe of the souson. At oa 2.0M concentercetion, the pn of solution is = 6.661 if we added water in this solution, the come entrasion of a solution will be decreased but theis is a minor chanse in ph due to decreasino of a clonc shenape