Question

... MUS Zeg A solution contains 1.06x10-4 M silver nitrate and 1.28x10 - Maluminum acetate. Solid sodium hydroxide is added slowly to this mixture. olu... 1 pts M 1 pts M A. What is the formula of the substance that precipitates first? ed... 1 pts M formula - 1 pts 2req mts 1 pts 2rea B. What is the concentration of hydroxide ion when this precipitation first begins? (OH) = 1 pts 2req M

Answer 1

A) Al(OH)₃ precipitates first.

B) hydroxide ion concentration when this first ppt begins 5.294*10^-11 (M).

The solution contains 1.06815² (M) Silver ritrate (AgNO3) and 1.28x 10 {m) aluminum acetate All et coo) 3: Solid Naor is being added slowly to this solution. NaOHght Ag NO3(aq) → Ag OH (s): + Na Nozlar) 0 (ppt) NaOH (8) + Allen Coo); (ar) → Al(OH)3(s) + CH₃COONa. : (ppt) . due to the addition of Naor, Agon& Alloh, may be Precipitated, We have to find out which one will : first precipitated out. Again, reaction quotient of Agoh precipitations g= [Ag+] [or] as Agon(s) Ag (aq) + 5ri (aq). 3=1.06X16? [or] as Ag mozkatu Ag trasy t worlag) . (1 mole of Ag Noz dissociates - into tmol of Agt & Noz ions) Similarly reaction quotient of Al(OH)3 Precipitation, 8-[A1t3].[6H] 28 Al(OH)= Altlary +30H (mg) 3 1-28x16% [ort] 3 ax Allentzero),(9) = Atien) . t. 3 eliz coo (ar) (I mole. Alleth Coo), dissociates into tmol of Alt3 and 3 moles of cthers ions]

A substance starts precipitating at in the solution, When its reaction quotient (8) is greater than equal to tits ksp valice. B) Ksp. for simplicity we will take g = ksp. Now for Ag oH , Ksp = 2x. 158 (Literature value) 1:06x10² [ok] = 2x108 (equating Bik sp for Agor) .. [on] = 2x108x = 1.887 xló 6(my When oth concentration in the solution becomes .. 1-88 7x10b (M) Agon starts precipitation. Now for AllOH)3 's Kspzlo9 x 1533 (Literature value) 1.28x16? []} = 1.5X1633 .! ör, [or]} = 1.981033 = 10484x1531 Issen 128.310-23 ...[0] = (1.484x1630)/3 = 5.294x16 "(m) - . When oh concentration in the solution becomes .:5.294% 16"(m), Al(OH)3 starts precipitation. [or] for. Al(OH)3 ppt. . 5.294x10h : 2.806X60B <1 [or] for Agol Pet T-887815-6 2. [or] for Ai (oh); ppt <[57] for Ag oH ppt. - i Al(OH)3 will be first precipitated out Th. concentration will be 5.294x10" (M) when first precipitation will occur...