Question

When `1.5mol` of `CuCI_(2).2H_(2)O` is dissolved in enough water to make `1.0L` of solution.
Given: `K_(f)CuCI^(Theta) 1.0 (K_(f)` is the formation constant of `CuCi^(o+))`
`[CiCI^(o+)]` in solution is
A. `1.0 M`
B. `2.0 M`
C. `3.0 M`
D. `0.5 M`

Answer 1

Correct Answer - B
`CuCI_(2).2H_(2) O rarr Cu^(2+) + 2CI^(Theta) + 2H_(2)O`
`{:(,Cu^(2+)+,CI^(Theta)rarr,CuCI^(Theta),),("Initial mol",1.5,2xx1.5=(3.0),0,),("At equilibrium",1.5-x,3.0-x,x,):}`
`K_(f) = ([CuCI^(o+)])/([CI^(2+)][CI^(Theta)]) = 1.0`
`rArr (x)/((1.5-x)(3.0-x)) = 1.0`
`rArr x = 4.5 - 4.5x +x^(2)`
`rArr x^(2) - 5.5x + 4.5 = 0`
`x = (5.5+-sqrt((5.5)^(2)-4(4.5)))/(2),x = 10or 4.5`
`[CuCi^(o+)] = 1.0 M`