Question

Define osmosis.

Answer 1

Hint: Osmosis is the process associated with the osmotic pressure along the medium involved in the process. It is also, one of the colligative properties for the solutions in action.

Complete Solution :
Let us study about the basic terms related to osmosis;
Osmosis-Osmosis is a process by which the solvent from a low concentrated solution passes to the high concentrated solution through a semipermeable membrane till the solution reaches equilibrium.
- It is a passive and spontaneous process happening without any expenditure of energy. It just involves the movement of molecules from one region to another till equilibrium.
- Osmosis is the act that equalises the concentration on both sides of a membrane. The solvent tends to be passed as the solute particles cannot pass through the membrane. This passing will continue till the solutions reach equilibrium with each other. Thus, osmosis is a thermodynamically favourable process.

- General examples where the phenomenon of osmosis takes place-
1. Red blood cells
2. Roots of plants
Semi-permeable membrane-
It is a thin membrane which will allow a certain size of molecules (generally small) to pass through it but not others.

Note: Do note that any solvent can undergo the process of osmosis which also includes gases and supercritical liquids.
Osmotic pressure is the external pressure that would be responsible for the zero-net movement of solvent across the membrane. In short, it is just the extra pressure to stop the phenomenon of osmosis. This can be mathematically stated as,
$$\pi =MRT$$
where,
$\pi$ = osmotic pressure
M = molarity of the solution
R = ideal gas law constant
T = absolute temperature