Question

Questions 1 & 2 refer to the solubility of lead chromate, PbCr04: PbCrO4(s) = Pb2+(aq) + Cro4? (aq) 1. The Ksp for PbCrO4 is 2.0 x 10-16 at 25 °C. What is the solubility of PbCr04 in mol L´?? a) 1.4 x 10-8 b) 2.8 x 10-8 c)2.0 x 10-16 d) 7.1 x 107 e) 5.0 x 1015 2. If 5.0 mL of 1.0 x 10-M Pb(NO3)2 is added to 5.0 mL of a solution of 1.0 × 10-1° M K Cr04, which statement is correct? a) The ionic product is 1.0 × 10-15 and PbCrO4(s) precipitates. b) The ionic product is 2.5 x 10-16 and PbCrO4(s) does not precipitate. c) The ionic product is 1.0 x 10-15 and PbCrO4(s) does not precipitate. d) The ionic product is 2.5 x 10-16 and PbCrO4(s) precipitates. e) none of the above 3. What is the electronic configuration of Mn2+? a) 152 2s? 2p 3s 3p 4.s2 3d' b) 1s? 2s2p 3s2 3pº 4s' 3d? c) 1s 2s 2p 3s2 3p 3d d) 1s 2s 2p 3s2 3p 3d e) 152 252 2p 3s2 3pº 452 3d 4. What is the systematic name for the coordination compound, K2[Mn(OH)2(CN)4]? a) potassium tetracyanidodiaquamanganate (III) b) potassium tetracyanidodiaquamanganate (II) c) potassium diaquatetracyanidomanganate (III) d) dipotassium diaquatetracyanidomanganate (II) e) potassium diaquatetracyanidomanganate (II) 5. The Ks for silver chloride is 1.8 x 10-10 at 25 °C. What is the solubility of silver chloride (in mol L"') in 0.025 M tin(IV) chloride solution? a) 8.5 x 10-5 b) 6.7 x 10-8 c) 7.2 x 10-9 d) 1.8 x 10 e) 1.3 x 10-5

Hi could you please provide detailed workings for this question? thanks!

Answer 1

1) Solubility equilibrum: PbCror(s) Pb2+ (aq) + Cro?- (aq) Solubility product of PbCrO4, Kº = [Pb2+ ][cro-]= 2.0x10–16 2 Pb2+ (aq) + Cro? (aq) ICE table: PhCror(s) I(M): C(M): E(M): + +s 9 Solubility product, K., = [Pb* | Cro?] 2.0x10-16 = (s)x(s) = 52 s = 2.0x10-16 = 1.4x10®M Thus, molar solubility of Pb Cro, in pure water is 1.4x10M Thus, the correct option is 'a'

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2) Solubility equilibrum : PbCro. (8) 2 Pb2+ (aq) + Cro- (aq) Solubility product of PbCrO, KA = [Pb2+ TC70-7=2.0x10-16 Initial concentrati on of Pb2*, 2+7 5.0 mL x(1x10-M) Pb 4 Janzia 15.0+ 5.0) mL = 5x10 MM 5.0 mL x(1x10-10M) Initial concentration of Crom. [Cro Jaia 25x10-11 MM (5.0+ 5.0) mL Ionic product of PbCron, low = [Pb2+ ]utna (C03 ) uta = (5x10^)(5*10-4) * 2.5x10-16 Solubility product of BaCrO., K. = [BaCro?-]= 2.0x10-16 Since Q. > Kg, precipitates. Thus, the correct option is 'd'