The correct order of solubility of the given salts in water at 298 K is array|l|l| Salt & Ksp at 298 K \ AgBr & 5.0 10-13 \ Zn(OH)2 & 1.0 10-15 \ Hg2Cl2 & 1.3 10-18 \ array
- Zn(OH)2 > AgBr > Hg2Cl2
- Hg2Cl2 > Zn(OH)2 > AgBr
- AgBr > Zn(OH)2 > Hg2Cl2
- Hg2Cl2 > AgBr > Zn(OH)2
Answer
(1) Zn(OH)2 > AgBr > Hg2Cl2
Solution
Calculating the molar solubility (s) for each salt:
1. AgBr: Ksp = s2 = 5.0 10-13 s = 50 10-14 7.07 10-7 mol L-1
2. Zn(OH)2: Ksp = 4s3 = 1.0 10-15 s3 = 2.5 10-16 = 250 10-18 s 6.3 10-6 mol L-1
3. Hg2Cl2: Hg2Cl2 Hg22+ + 2Cl-, so Ksp = 4s3 = 1.3 10-18 s3 = 0.325 10-18 s 6.9 10-7 mol L-1
Comparing solubilities:
Zn(OH)2 (6.3 10-6) > AgBr (7.1 10-7) > Hg2Cl2 (6.9 10-7)
Answer: (1)