Question

Should a precipitate of barium fluoride be obtained when `100mL` of `0.25M NaF` and `100mL` of `0.015M Ba(NO_(3))_(2)` are mixed. `K_(sp)` of `BaF_(2) = 1.7 xx 10^(-6)`

Answer 1

`BaF_(2) hArr Ba^(2+) + 2F^(Θ)`
`K_(sp) [Ba^(2+)]|| [F^(Θ)]^(2) = 1.7 xx 10^(-6)`
`[F^(Θ)] = (100mL xx 0.25 M)/(200mL) = 0.125 M` and
`[Ba^(2+)] = (100mL xx 0.015M)/(200mL) = 0.0075M`
Ionic product of `BaF_(2)`
`IP = [Ba^(2+)] [F^(Θ)]^(2) = (7.5 xx 10^(-3)) (0.125)^(2) = 1.2 xx 10^(-4)`
Since ionic product `gt K_(sp)`
`:.` precipitation occur