Arrange the following in increasing order of solubility product : Ca(OH)2, AgBr, PbS, HgS
- PbS < HgS < Ca(OH)2 < AgBr
- HgS < AgBr < PbS < Ca(OH)2
- HgS < PbS < AgBr < Ca(OH)2
- Ca(OH)2 < AgBr < HgS < PbS
Answer
(3) HgS < PbS < AgBr < Ca(OH)2
Solution
Approximate Ksp values at 298 K (NCERT table):
HgS: 4 10-53
PbS: 8 10-28
AgBr: 5.0 10-13
Ca(OH)2: 5.5 10-6
Increasing order: HgS < PbS < AgBr < Ca(OH)2
(Sulphides of Hg and Pb are among the least soluble salts; Ca(OH)2 is sparingly soluble but far more soluble than AgBr.)
Answer: (3)