Q. A solution which is $10^{- 3}M\ each\ in\ Mn^{2 +},\ Fe^{2 +},\ Zn^{2 +}\ and\ Hg^{2 +}$ is treated with $10^{- 16}$ M sulphide ion. If $K_{sp}\ of\ MnS,\ FeS,\ ZnS\ \ and\ HgS\ are\ 10^{- 15},\$ $10^{- 23},\ 10^{- 20}\ and\ 10^{- 54}$ respectively, which one will precipitate first?

A) $FeS$
B) $MgS$
C) $HgS$
D) $ZnS$
Explanation

(c)
On the basis of precipitation concept an electrolyte will be precipitated firstly whose ionic product is exceeded to its solubility product. In similar ionic conc. of cations, an electrolyte is precipitated firstly for which $K_{sp}$ is lower. In these electrolytes $MnS,\ FeS,\ ZnS\ \ and\ HgS,\ HgS$ is precipitated firstly.

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.

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