States of Matter

The illumination of a beam of light due to scattering on collision with certain particles is called Tyndall effect . Milk shows Tyndall effect.

This is the correct answer, as all these statements prove that air is a mixture. The amounts of gases present in air at different places varies, though only marginally. The properties of air are the properties of its constituents. Air supports combustion due to the presence of oxygen in it, it turns lime water milky due to the presence of carbon di oxide in it. The different gases present in air can be separated by the physical process of fractional distillation of liquid air.

Diffusion occurs fastest in gases because gas molecules have the most kinetic energy and are far apart, allowing rapid random movement. In liquids, diffusion is slower due to stronger intermolecular forces. In solids, diffusion is extremely slow as particles are fixed in position.

An alloy is a homogeneous mixture of two or more solid elements, where one is a metal. Examples include brass (copper + zinc) and steel (iron + carbon). Air is a gas mixture, alcohol in water is a liquid-liquid solution, not solid-solid.

Covalent compounds are typically nonpolar or weakly polar, making them soluble in organic solvents (like benzene, ether, chloroform) which have similar intermolecular forces. Water is polar and does not dissolve most covalent compounds. Acids may or may not dissolve them depending on reactivity.

A solid solution is a homogeneous mixture of two or more solids where one solid is dissolved in another. Alloy is an example of a solid solution. Solvent is the dissolving medium, solute is what gets dissolved - these are roles, not the solution itself.

An emulsion is a colloidal dispersion of liquid droplets in another liquid (e.g., milk, mayonnaise). Foam is gas in liquid, gel is liquid in solid matrix, smoke is solid particles in gas. Only emulsion fits liquid-in-liquid dispersion.

Sugar is a singular subject, so it needs the third-person singular verb form 'dissolves' in the present simple tense. 'Dissolve' would be used with plural subjects like 'They dissolve'. 'Melts' refers to changing from solid to liquid with heat, not mixing in water. 'Drowns' is incorrect as drowning applies to living things that suffocate in water.

The temperature dependence of liquid viscosity is the phenomenon by which liquid viscosity tends to decrease (or, alternatively, its fluidity tends to increase) as its temperature increases. 

Evaporation causes cooling. When a liquid evaporates, it absorbs the latent heat of vapourization from its surroundings to regain the energy lost during evaporation. This absorption of energy makes surrounding cool.

Surface tension decreases when temperature increases because cohesive forces decrease with an increase of molecular thermal activity. The influence of the surrounding environment is due to the adhesive action liquid molecules have at the interface.

Adhesion of water to the walls of a vessel will cause an upward force on the liquid at the edges and result in a meniscus, which turns upward. The surface tension acts to hold the surface intact. Capillary action occurs when the adhesion to the walls is stronger than the cohesive forces between the liquid molecules.

Mercury's key property for thermometer use is its uniform thermal expansion - it expands and contracts predictably with temperature changes. This makes it ideal for accurate measurement. Option C is correct. Being a liquid or metal alone (options A and B) isn't sufficient - many substances share those properties.

Mercury has been known as 'quicksilver' since ancient times due to its silvery appearance and liquid state at room temperature. The term 'quick' in this context means 'alive' or 'moving' - referring to how mercury flows and spreads rapidly. Silver Liquid and Quick Liquid are not the recognized names for mercury.

It is an organic substance that can withstand extreme environment conditions.