... tan ca Mg(OH)2 bng : 0,84 .10 /10 00.58 =1, 4 .1 0-4 mol/l Nh th [Mg ]= 1, 4 .1 0-4 mol/l 2+ [OH ] = 2 .1, 4 .1 0-4 =2,8 .1 0-4 mol/l 32 TMg(OH)2 = 1, 4 .1 0-4 .(2,8 .1 0-4 )2 = 1, 1 .1 0 -1 1 Vy: 4.2 CC YU T HNG N TAN ... 1 0-6 ,4 HCO-3 H+ + CO3 2- vi hng s axit K2 = 1 0 -1 0,3 Ta thy: K1/K2 = 1 0-6 ,4 /1 0 -1 0,3 = 10 4 - H3PO4 phõn li theo ba nc cú hng s axit tng ng cú cỏc giỏ tr l pK1 = 2 ,12 ; pK2 = 7, 21; pK3 = 12 ,36 Nh vy ... trỡnh: [H+]2 = 1 0-4 ,75 .1 0-4 1 0-4 ,75 [H+] [H+]2 + 1 0-4 ,75 [H+] 1 0-4 ,75 = Gii ta c [H+] = 0, 81 1 0-4 ,38 v pH = -lg[H+] = 4,470 Nhng nu b qua [H+] cnh CA thỡ pH = 0,5 4.75 0,5.lg1 0-4 = 2, 375 +...