Osmosis and Osmotic Pressure - UNSOLVED PRACTICE SET
Chapter: Solutions | Topic: Osmosis and Osmotic Pressure
OSMOSIS AND OSMOTIC PRESSURE - UNSOLVED PRACTICE SET
Topic: Osmosis and Osmotic Pressure
Multiple Choice Questions
Q1. Osmosis is the movement of solvent molecules from:
- Higher concentration of solution to lower concentration of solution through a semipermeable membrane
- Lower concentration of solution to higher concentration of solution through a semipermeable membrane
- Higher concentration of solute to lower concentration of solute
- Lower concentration of solute to higher concentration of solute
Q2. The osmotic pressure (π) of a dilute solution is given by the van 't Hoff equation:
- π = nRT/V
- π = nV/RT
- π = RT/nV
- π = V/nRT
Q3. A solution with lower osmotic pressure than another is called:
- Hypertonic
- Hypotonic
- Isotonic
- Osmotic
Q4. The phenomenon of reverse osmosis occurs when:
- Pressure equal to osmotic pressure is applied
- Pressure greater than osmotic pressure is applied
- No pressure is applied
- Pressure less than osmotic pressure is applied
Q5. Which of the following is isotonic with human blood plasma?
- Distilled water
- 0.9% NaCl solution
- 5% glucose solution
- 10% NaCl solution
Q6. The molar mass of a solute determined by osmotic pressure measurement will be:
- Higher than actual if the solute dissociates
- Lower than actual if the solute dissociates
- Accurate regardless of dissociation
- Higher than actual if the solute associates
Short Answer Questions
Q7. Define osmosis and osmotic pressure. What is a semipermeable membrane? Give one example.
Q8. Calculate the osmotic pressure of a solution containing 5.85 g of NaCl in 1 L of solution at 27°C. (Assume complete dissociation, R = 0.0821 L·atm/K·mol)
[Given: Molar mass of NaCl = 58.5 g/mol]
Q9. Differentiate between:
(a) Endosmosis and exosmosis
(b) Hypertonic, hypotonic, and isotonic solutions
Q10. Why is osmotic pressure considered the most suitable colligative property for determining the molar mass of macromolecules like proteins and polymers?
Q11. Your grandmother preserves mangoes in concentrated sugar syrup (brine). Explain how osmosis helps in preserving the mangoes and preventing bacterial growth.
Q12. Why do red blood cells swell up when placed in distilled water but shrink when placed in concentrated salt solution? Explain using the concept of osmosis.
Long Answer Questions
Q13. Discuss osmosis and osmotic pressure in detail:
(a) Definition of osmosis and osmotic pressure
(b) Semi-permeable membranes — natural (cell membranes, pig's bladder) and artificial (cellophane, parchment paper)
(c) van't Hoff equation for osmotic pressure: π = CRT = nRT/V
(d) van't Hoff-Boyle's law, van't Hoff-Charles' law, and van't Hoff-Avogadro's law for dilute solutions
(e) Determination of molar mass using osmotic pressure
(f) Experimental methods: Berkeley and Hartley's method, Pfeffer's method
Q14. Explain the biological and industrial applications of osmosis:
(a) Osmosis in plant cells — turgor pressure, plasmolysis, wilting
(b) Osmosis in animal cells — red blood cells in different tonic solutions, dialysis in kidneys
(c) Reverse osmosis for water purification — principle, membrane technology, energy requirements
(d) Food preservation — pickling, jam and jelly making, salting of fish and meat
(e) Intravenous fluids in medicine — why 0.9% NaCl and 5% glucose are isotonic with blood
Q15. Osmosis and reverse osmosis are critical for India's water security and health. Discuss:
(a) Why reverse osmosis (RO) plants are essential in Chennai and other coastal cities facing water scarcity
(b) The working principle of domestic RO water purifiers used in millions of Indian homes
(c) Why farmers in saline areas of Gujarat and Rajasthan use drip irrigation to manage soil osmotic stress
(d) The health impact of drinking RO-purified water long-term — demineralisation concerns and remineralisation solutions
Numerical / Application-Based Problems
Q16. A solution containing 1.5 g of a protein per 100 mL has an osmotic pressure of 5.72 mmHg at 25°C.
(a) Calculate the molarity of the protein solution.
(b) Calculate the molar mass of the protein.
(c) Why is this method particularly suitable for proteins compared to other colligative properties?
[Given: R = 0.0821 L·atm/K·mol]
Q17. Human blood plasma has an osmotic pressure of approximately 7.65 atm at 37°C.
(a) Calculate the total concentration of solute particles in blood plasma.
(b) A patient is given an IV drip of 0.9% NaCl (w/v). Calculate the osmotic pressure of this saline solution at 37°C and verify if it is isotonic with blood.
(c) If a nurse accidentally administers distilled water IV, calculate the osmotic pressure difference and explain why this is life-threatening.
[Given: R = 0.0821 L·atm/K·mol, assume NaCl dissociates completely]
Q18. A reverse osmosis plant in Chennai desalinates seawater containing 35 g/L of NaCl at 25°C.
(a) Calculate the osmotic pressure of seawater (assume i = 2 for NaCl).
(b) Calculate the minimum pressure required for reverse osmosis.
(c) The plant operates at 70 bar (≈ 69 atm) and produces 10 million litres of fresh water daily. Calculate the theoretical energy required per day and the cost at ₹ 6 per kWh. (1 L·atm = 101.3 J)
(d) Explain why RO water is slightly acidic and how remineralisation improves its taste and health benefits.