The precipitation of aluminum hydroxide, Al(OH)_3 (K_sp)=1.3 x 10^{-33}), is sometimes used to purify water.
At what pH will precipitation of Al(OH)_3 begin if 5.70 lb of aluminum sulfate, Al_2(SO_4)_3, is added to 2050 gallons of water (with a negligible change in volume)?
Below are some potentially useful conversion factors.
1 lb = 453.6 g
1 gallon = 4 quarts
1 quart = 0.946 L