River water in a chalky agricultural area may contain Ca2+, Mg2+, − 2
3
CO , −
3
HCO , Cl
− and −
3
NO
ions. In a waterworks, such water is treated by adding a calculated quantity of calcium hydroxide.
What will be precipitated following the addition of calcium hydroxide?
A CaCl2
B CaCO3
C Ca(NO3) 2
D Mg(NO3)2

Question

River water in a chalky agricultural area may contain Ca2+, Mg2+, − 2
3
CO , −
3
HCO , Cl
− and −
3
NO
ions. In a waterworks, such water is treated by adding a calculated quantity of calcium hydroxide.
What will be precipitated following the addition of calcium hydroxide?
A CaCl2
B CaCO3
C Ca(NO3) 2
D Mg(NO3)2

aaronq · Answer

look at the solubilities $(e.g.~K_{sp})$ of the compounds listed.