Liquid State
The matter in liquid state have a definite volume and no definite shape.
Examples : Water, blood, benzene, alcohol, milk, petrol, cooking oil, juice, cold drink etc.
*Properties of Liquids
(a) Liquid do not have fixed shape but have a fixed volume : The liquids have a fixed volume due to strong inter particle forces of attraction in them which are strong to keep the particles together. But these forces are not strong enough to keep the particles in fixed position, therefore, liquids do not have a fixed shape, they take up the shape of vessel in which they are placed.
(b) Liquids are not rigid but have a property to flow : Liquids can flow and change shape due to larger inter particle distances and weaker forces of attraction in them, than solids. Thus liquids are not rigid but they possess fluidity (i.e. they have property to flow) Relative fluidity of liquids differ from one liquid to other. e.g. water flows faster than honey.
(c) Liquids possess the property of Diffusion : Due to larger inter particle distances in liquids than in solids, the particles of a liquid have more freedom of motion than solids. Thus solids, liquids and gases all can diffuse into liquids as discussed below:
(i) Diffusion of solids into liquids: When a crystal of copper sulphate or potassium permanganate (solid) is added to water (liquid), the particles of CuSO4 or KMnO4 quickly diffuse in between the particles of water to form a solution.
(ii) Diffusion of liquids into liquids: When water is added to alcohol or vice-versa, the two liquids quickly diffuse into each other to form a solution.
(iii) Diffusion of gases into liquids: Some gases especially O2 and CO2 diffuse into water i.e. dissolve in water. So that aquatic animals can breathe under water due to presence of dissolved oxygen in water
Thus solids, liquids & gases – all can diffuse into liquids. However, the rate of diffusion of liquids is much higher than that of solids.
*Rate of diffusion of different liquids :- Different liquids have different rates of diffusion. For example a drop of blue or red ink diffuses faster than a drop of honey into water.
*Rate of diffusion increase with rise in temperature :- Rate of diffusion increases with rise in temperature, hence sugar dissolves much more quickly in hot water than in cold water.