JAMB - Chemistry (2008 - No. 13)
In the course of purifying water for town supply the water is passed through large settlings tanks, containing sodium aluminate (III) to remove?
large particles
germs
fine particles
odour
Explication
Potash alum [kAl(S\({O}_4\))\(_2\)] n sodium aluminate (ii) (NaHCO\(_2\)) are added to cause coagulation.
As fine particles to clump together, forming large particles heavy enough to settle at the bottom of the tanks as impurities.