NTA Abhyas NEET2020ChemistryIonic EquilibriumPractice
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 - 13 , 10 –18 , 10 –24 and 10 –53 respectively, which one will precipitate first ?
Options
- AFeS
- BMgS
- CHgS
- DZnS
Correct answer
C. HgS
Step-by-step solution
[S 2 - ] need for precipitation of FeS = 1 0 - 1 8 1 0 - 3 = 1 0 - 1 5 M MnS = 1 0 - 1 3 1 0 - 3 = 1 0 - 1 0 M HgS = 1 0 - 5 3 1 0 - 3 = 1 0 - 5 0 M ZnS = 1 0 - 2 4 1 0 - 3 = 1 0 - 2 1 M Thus minimum [S 2 - ] for precipitation is for HgS it will be precipitated first.