A 1.00 molar aqueous solution of trichloroacetic acid (CCl₃COOH) is heated to its boiling point. The solution has the boiling point of 100.18 °C. Determine the van’t Hoff factor for trichloroacetic acid. ( for water = 0.512 K kg mol⁻¹).
Δ = im
(373.18 – 373) K = i × 0.512 K kg mol⁻¹ × 1 m
0.18 K = i × 0.512 K kg mol⁻¹ × 1 m,
i = 0.35
(373.18 – 373) K = i × 0.512 K kg mol⁻¹ × 1 m
0.18 K = i × 0.512 K kg mol⁻¹ × 1 m,
i = 0.35
Explain why on addition of 1 mol of NaCl to 1 litre of water, the boiling point of water increases, while addition of 1 mol of methyl alcohol to one litre of water decreases its boiling point.
The osmotic pressure of a solution is directly proportional to
(a) the molecular concentration of the solute.
(b) the absolute temperature at a given concentration.
(c) the lowering of vapour pressure.
(d) all the above.
The vapour pressure of pure liquids A and B at 400 K are 450 and 700 mm Hg respectively. Find out the composition of liquid mixture if total pressure at this temperature is 600 mm Hg.
State Raoult’s law for a solution containing nonvolatile solute. What type of deviation from Raoult’s law is shown by a solution of chloroform and acetone and why?
Define the following terms :
(i) Mole fraction
(ii) Isotonic solutions
(iii) Van’t Hoff factor
(iv) Ideal solution
(i) Write the colligative property which is used to find the molecular mass of macromolecules.
(ii) In non-ideal solution, what type of deviation shows the formation of minimum boiling azeotropes?
When mercuric iodide is added to the aqueous solution of potassium iodide, the:
(a) Freezing point is raised
(b) Freezing point does not change
(c) Freezing point is lowered
(d) Boiling point does not change
State Raoult’s law for a solution containing nonvolatile solute. What type of deviation from Raoult’s law is shown by a solution of chloroform and acetone and why?
Explain the following observations:
(i) Copper atom has completely filled d orbitals (3d¹⁰) in its ground state, yet it is regarded as a transition element.
(ii) Cr²⁺ is a stronger reducing agent than Fe²⁺ in aqueous solution.
In the following ions:
Mn³⁺, V³⁺, Cr³⁺, Ti⁴⁺
(Atomic no: Mn = 25, V = 23, Cr = 24, Ti = 22)
(a) Which ion is most stable in an aqueous solution?
(b) Which ion is the strongest oxidizing agent?
(c) Which ion is colourless?
(d) Which ion has the highest number of unpaired electrons?
Explain the solubility rule “like dissolves like” in terms of intermolecular forces that exist in solutions.
What is meant by positive deviations from Raoult’s law ? Give an example. What is the sign of H for positive deviation ?