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 freezing point vapor pressure elevation depression lowering b) An example of a strong soluble base Pb(OH) Ba(OH)2 Cu(OH)2 AgOH c) A cation that is expected to act as a weak acid in water Mg? (aq) Pb?"(aq) Ag (aq) K*(a) d) A rate law that is second order heterogeneous rate -k[A] rate -k[A] rate-k[A][B] ratek 5) The molecular complex Ca(CN)dissociates in water by the process Ca(CN):(aq) 5 Cd?"(aq) + 4 CN Ke-1.3 x 10" The initial concentration of Ca(CN)/2- in an aqueous solution is 0.0360 M. No Cd2+ or CN ions are initially present. What is the concentration of Cdion present when equilibrium is achieved? [12 points)

Answer 1

a) The answer is "OSMOTIC PRESSURE " because
osmotic pressure (II)
,
II = MRT

where M is molarity of the solute particles, R is gas constant , and T is temperature.

and all others depend on Molality of the solute.

b) Ba(OH)2 , because as we move left to right in a periodic table , basicity dec n acidity inc.

and also as we move from top to down in a group ,the solubility of Hydroxides increases in a group.(because of dec in lattice energy of the salt and increase in coordination number of the metal ion).

c) K+ produces a strong base , and weak acid.

d) rate = k[A][B] ,it depends on 2 diff reactants(heterogeneous) and order is 2.