Two solid compounds A "and" B dissociate into gaseous products at 20^(@)C as (i) A(S)hARrA'(g)+H_(2)S(g) (ii) B(S)hArrB'(g)+H_(2)S(g) At 20^(@)C pressure over excess solid A "is" 50mm and that over excess solid B "is" 68mm find, (a) The dissociation constant of A "and" B (B) Relative no. of moles ofA "and" B' in the vapour phase over a mixture of solid A "and" B. (c) Show that the total pressure of the gas over the solid mixture would be 84.4mm

Two solid compounds A "and" B dissociate into gaseous products at 20^(

1.	Two solid compounds A "and" B dissociate into gaseous products at 20^(@)C as (i) A(S)hARrA'(g)+H_(2)S(g) (ii) B(S)hArrB'(g)+H_(2)S(g) At 20^(@)C pressure over excess solid A "is" 50mm and that over excess solid B "is" 68mm find, (a) The dissociation constant of A "and" B (B) Relative no. of moles ofA "and" B' in the vapour phase over a mixture of solid A "and" B. (c) Show that the total pressure of the gas over the solid mixture would be 84.4mm
Answer» Solution :`A(S)hArrA'(g)+H_(2)S(g) B(s)hArrB'(g)+H_(2)S(g)` `A(S)hArrA'(g)+H_(2)S(g) P=50mm rArr P_(H_(2)S=P_(A).=P//2=25mm` `B(S)hArrB'(g)+H_(2)S(g) P=68mm rArr P_(H_(2)S=P_(B')=P//2=34mm` (i) `K_(P1)=(25)^(2)=625MM^(2)` `K_(P2)=(34)^(2)=1156mm^(2)` (ii) Ratio of moles is same as that of PARTIAL pressure so A`(S) hArr A,(g) + H_(2)S(g)` `P_(1) P_(1)+P_(2)` `B(S) hArr B'(g) + H_(2)S(g)` `P_(2) P_(2)+P_(1)` `K_(p1)=P_(A.)xxP_(H_(2)S=P_(1)(P_(1)+P_(2))` .....(i) `K_(p2)=P_(B.)xxP_(H_(2)S=P_(2)(P_(1)+P_(2))` .....(ii) `(K_(p1))/(K_(P2))=(P_(1))/(P_(2))=(625)/(1156)` (iii) TOTAL pressure `=P_(1)+P_(2)+(P_(1)+P_(2))=P_(1)+P_(2))` (i)+(ii)`=(p_(1)+P_(2))^(2)` `sqrtK_(P1)+K_(P2)=P_(1)+P_(2)` `P_(T)=2xx(sqrtK_(P1)+K_(P2))=84.4mm`.