Consider three metal chlorides x, y and z, where x is water soluble at room temperature, y is sparingly soluble in water at room temperature and z is soluble in hot water. x, y and z are respectively
- AgCl, Hg2Cl2 and PbCl2
- CuCl2, AgCl and PbCl2
- AlCl3, PbCl2 and BaCl2
- MgCl2, AgCl and AlCl3
Answer
(2) CuCl2, AgCl and PbCl2
Solution
x: water soluble at room temperature — CuCl2 (also MgCl2, AlCl3, BaCl2); AgCl is not.
y: sparingly soluble at room temperature — AgCl (white precipitate of group I).
z: soluble in hot water — PbCl2. In salt analysis, the group I precipitate is boiled with water: PbCl2 dissolves, AgCl and Hg2Cl2 do not.
Option (1): x = AgCl is not water soluble. Option (3): z = BaCl2 is soluble even in cold water. Option (4): z = AlCl3 is soluble in cold water.
x, y, z = CuCl2, AgCl, PbCl2
Answer: (2)