Question

The values of `K_(sp)` of two sparingly soluble salts, Ni`(OH)_(2)` and AgCN are `2.0xx10^(-15) and 6.0xx10^(-17)`, respectively. Which salt is more soluble ? Explain.

Answer 1

Correct Answer - `S(Ni (OH)_(2))=5.8xx10^(-5) M, S (AgCN) = 7.8xx10^(-9) M, Ni (OH)_(2) ` is more soluble
`{:(Ni(OH)_(2),hArr,Ni^(2+),+,2OH^(-),,,),(s,,s,,2s,,,):}`
`K_(sp) = s (2s)^(2) = 4 s^(3 ) = 2.0 xx 10^(-15) `. This gives `s=5.8xx10^(-5)` mol `L^(-1)`
`{:(AgCN,hArr,"Ag"^(+),+,CN^(-),,,),(s,,s,,s,,,):}` or `s=sqrt(K_(sp))=sqrt(6.0xx10^(-17))=7.8xx10^(-9) ` mol `L^(-1)`