Q.(a) List out the essential properties of water. OR

(a) Water's essential biological properties include high specific heat, high heat of vaporisation, cohesion/surface tension, universal solvent ability, and the lower density of ice. (b) Medical and e-waste must be segregated, safely treated (sterilised/incinerated or recycled), and disposed of only through regulated, licensed channels.

(a) Water possesses several unique physicochemical properties, arising mainly from its polar nature and capacity to form hydrogen bonds, that make it essential to life. Its high specific heat capacity means it can absorb or release a large amount of heat with only a small change in its own temperature, helping to buffer both the internal temperature of organisms and the temperature of aquatic/terrestrial environments against rapid fluctuation. Its high heat (latent heat) of vaporisation means a large amount of energy is needed to convert liquid water to vapour, which is why evaporative cooling - such as sweating in humans or transpiration in plants - is such an effective way to dissipate excess body heat. Cohesion (attraction between water molecules) and the resulting surface tension, again due to hydrogen bonding, allow water to be pulled up as a continuous column through the narrow vessels of plant xylem (the cohesion-tension mechanism) and enable capillary action. Water is often called the universal solvent because its polarity lets it dissolve a very wide range of ionic and polar biomolecules (salts, sugars, amino acids), providing the medium in which almost all biochemical reactions of metabolism occur. Finally, water shows a density anomaly on freezing - unlike most substances, ice is less dense than liquid water, so it floats on the surface of water bodies rather than sinking; this ice layer insulates the water below it, keeping it liquid and allowing aquatic organisms to survive through freezing conditions.

…