Order Dilute Solutions and Electrochemistry

Order Dilute Solutions and Electrochemistry
1. Dry air was bubbled successively through a solution containing 0.018 kg of an ideal nonvolatile solute in 0.1 kg water
and pure water for sometime. The loss of mass of solution was 2.94 g and that of the pure solvent 60 mg. What is the
ratio of the molar mass of solute to that of the solvent? (Assume the solution to be a dilute one)
2. The total vapour pressure, P mm, at 30qC for mixture of Benzene and Toluene (behaving ideally) conforms the equation Pmm = 32.1 (18.6 u x) where, x is the mole fraction of benzene in the liquid phase in equilibrium with vapour.
Calculate the vapour pressures of pure benzene and pure toluene. Further calculate the composition of the vapour at
this temperature for x = 0.5.
3. Calculate Kf
, the molal freezing point constant for a certain solid solvent, given that the enthalpy of fusion per mole
is 4.6 kcal, the melting point is 80qC and the molar mass = 128 g/mol.
4. A solution of m grams of glucose in a kilogram of water is cooled to 0.5qC. It is observed that approximately 250 g
of ice separates out. Kf
of water = 1.86 deg/molal. Calculate m (M for glucose = 180 g/mole).
5. One molal solution of benzoic acid in a solvent X boils at 81.5qC. The normal boiling point of the solvent is 80.1qC
assuming that (i) the usual laws of dilute solutions apply and (ii) the solute is 89.5% dimerized, Calculate Kb for the
solvent X
Order Dilute Solutions and Electrochemistry
6. Consider Pb Sn2 o Pb2 Sn
Eqvalues – Pb o Pb2 2e ; (0.13 V)
Sn2 2e o Sn ; (0.14 V). Calculate the ratio concentration of the ions
7. When the electric current is passed through silver nitrate solution using silver electrodes, 0.2503 g of silver is deposited
(Eq.wt = 108). In series with this electrolytic cell is another cell in which dil.H2
SO4