Question

Hydrogen sulfide dissociates according to the following equation:

In a mixture of the three gases at 25 oC, the concentrations (not at equilibrium) were      found to be [H2] = 0.0026 M, [S2] = 0.0013 M and [H2S] = 0.0077 M

a)    What is the value of the reaction quotient, Qc, of the mixture

b)   Given that Kc = 2.3 x 10-4 at 25 ^oC is the system at equilibrium?

c)    If not, will the reaction proceed in the forward direction or will the reaction proceed     in the reverse direction as equilibrium is achieved?

d)    What is the value of Kp at 25 oC for this reaction? (Giver R = 0.0821 L atm/ K mol)

Answer 1

Page : ANSWER kan From the vant hoff reaction of Agro RT in terms of activity If we stale activity concentration then eduation becomes the 2 r = -Rienke ke - е. RT where, Hea eduilibrium constant A r = standard gibbs free enesgy change Re enivessal gas con 3tom 4. AG 2 Ash + RT ln ge Ash = -RT ln ke + RT ln ke If it I ge < uel » spontaneous reaction [Arra-ve ederilibrium [ash=0 Se ke irit [ge y he » own spontaneaus reaction [342? +ve] where, Sea Co-efficient of concentration T eoneentration of produet n concentration of reactant CS

Page: 3 AN kp? Иe X Ceo RT Po Coa Standard concentration alim То 2 Poz Standard pressure al atm universal gas constanta 0.082 Leadm. mot! at as e a (25+ 273) 29 su [total no. of males of product]- (total no. of males of seaetant 2 Ana [total له (I + ķ)-1 1/2 77 1/2 I X0082x298 is 2.3x10a Kp? X 3 2 1.136 x 10 value of up a 1-136xós 2 CS

Page : 2 ANSWER H₂S dissociates like this H₂S H₂ Ž SL 1/2 : Se [H2 ] [52] [H25] 1/2 0.0026 % (0.0013) 0.0077 0.0026 X 0.0360 0.0077 2 0.012 ay value of seaction quotient (ge) = 0.012 by Kez 2,3 x 104 ey By Cheening the value, ие <ge This is non spontaneous reaction And backward reaction will favour cs