Question

4) For each of the following questions circle the correct answer. There is one and only one correct answer per problem. [5 points each] a) A colligative property whose value depends directly on the mole fraction of solute particles osmotic pressure boiling point elevation freezing point depression vapor pressure lowering b) An example of a strong soluble base Pb(OH)4 Ba(OH)2 Cu(OH)2 AgOH c) A cation that is expected to act as a weak acid in water Ag (aq) K+(aq) Mg2+(aq) Pb2+ (aq) d) A rate law that is second order heterogeneous rate = k [A] rate = k [A] rate = k [A] [B] rate =k 5) The molecular complex Cd(CN)42- dissociates in water by the process Cd(CN)42-(aq) = Cd2+(aq) + 4 CN- Kc = 1.3 x 10-17 The initial concentration of Ca(CN)42- in an aqueous solution is 0.0360 M. No Cd2+ or CN-ions are initially present. What is the concentration of Cd2+ ion present when equilibrium is achieved? [12 points]

Answer 1

Solution-y) a) Answer is Vapour pressure lowering Because lowering Depends on the solute of the vapour pressure solute of Mole fraction of the OP = X solute Psolvent Partial Pressure of Solvent, Change in Pressure g solution mole fraction of Solote 6) Answer is Baloh Because it is Because it is more soluble in water than other 3. COCOH)2 has negligible solubility, Pb(OH)4 AGOH is also a weak Bage. is a weak base

c) Answer is 24 P6² cag), because Lewis acid- strength goes i Post transition > Transition metal > Alkaline Earth > Alkoli Metal Metal Metal acid strength more and Pb2+ is down the group and has greater charge density. d) Answer is rate K CAT CB] bekuse twol (Gandu) of these four are not second order rate law. And option 2. rate = K(A)2 defies the word heterogeneous. Only Yate = k[A] (b) is heterogeneous (second order) rate law. which means it is the Arswen solution -s) Reaction given ca (caur cag) Z cd² 2+ (ag) tuld Ke= 1.3 x 1019 we are going to use ICE table.

ca (cada ca 2+ ucd I 0.03 60 0 -C ty tinc E 0.0360-xx TC tux Ке [ca2+] [4CN-]" [call) u 1-3x1017 [0-0360- x dow 0.0360-c y 00360 so 1.3x1017 256x 0.0360 1-3 X10'7 x 0-0360= 256 20 = (0.1828125 x 1620)\'s - 7. 1187 x 105 m * The Concentration Cd2+ ions present Equilibrium is achieved is 71187 xlos u g when