Comprehension:
Colligative Properties
Vapour pressure of a solution decreases when a non-volatile solute is added to a volatile solvent. There are many properties of solutions which are connected with this decrease of vapour pressure. These are: (1) relative lowering of vapour pressure of the solvent (2) depression of freezing point of the solvent (3) elevation of boiling point of the solvent and (4) osmotic pressure of the solution. All these properties depend on the number of solute particles irrespective of their nature relative to the total number of particles present in the solution. Such properties are called colligative properties.
Which of the following is an example of a synthetic semi-permeable membrane?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Cellophane
Cellophane, a film of regenerated cellulose, is a synthetic semipermeable membrane.
NCERT (2026-27 edition):
Osmosis and Osmotic Pressure – “… These membranes can be of animal or vegetable origin and these occur naturally such as pig’s bladder or parchment or can be synthetic such as cellophane. …”