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1. Milk of magnesia is a saturated solution of Mg(OH)2. Its solubility is 9.63 mg
Mg(OH)2/100 mL solution at 20oC. What is the pH of saturated Mg(OH)2 at 20 oC?
2. Hypochlorous acid, HOCl, is used in water treatment and as a disinfectant in
swimming pools. A 0.150 M solution of HOCl has pH of 4.18. Determine Ka for
hypochlorous acid.
3. What is the pH of a solution that is 0.00250 M CH3NH2(aq)? For methylamine,
CH3NH2, Kb = 4.2 x 10-4
.
4. What is the pH of a 0.0037 M solution of carbonic acid, H2CO3?
( Ka1 = 4.3 x 10-7
; Ka2 = 5.6 x 10-11 )
5. What is the pH of a buffer that is 0.12 M in lactic acid, HC3H5O3, and 0.10 M in
sodium lactate, NaC3H5O3? For lactic acid, Ka = 1.4 x 10-4
.
6. How many moles of NH4Cl must be added to 2.0 L of 0.10 M NH3 to form a
buffer whose pH is 9.00 ? (Assume that the addition of NH4Cl does not change
the volume of the solution)