What is the equilibirum concentration of each of the substance in the equilibrium when the initial concentration of Icl was `0.78 M`?
`2ICl(g) hArr I_(2)(g) + Cl_(2)(g), K_(c) = 0.14`

Explanation

Suppose at equilibrium
` [I_2(g) ]= [Cl_2(g) ]=x " mol " L^(-1)`
` {:(, 2lCl(g) , hArr , I_2 (g) , + , Cl_2(g) ),( " Initial conc." , 0.78 M ,, 0, ,0), ( " Conc. at Eq. ", (0.78-2x)M,, xM, ,xM):}`
Given that, ` " " K_c = 0.14 `
` " " K_c = ([I_2(g) ][Cl_2(g)])/([ICl(g) ]^(2))`
or ` " " 0.14 = (x xx x )/( (0.78 - 2x)^(2))`
or ` " " x^(2) = 0.14 (0.78 -2x)^(2)`
or ` " " x= sqrt(0.14 )(0.78 - 2x) = 0.374 (0.78 - 2x)`
or ` " " x= 0.292 - 0.74 8 x `
or ` " " 1.748 x = 0.292 `
or ` " " x= ( 0.292)/(1.748) = 0.167`
Hence , equlibrium concentrations will be as follow,
` [I_2(g) ] =[Cl_2(g) ] =x = 0.167 M`
` [Cl(g)] =0.78 -2x =0.78-(2xx 0.167) = 0.446 ` M