Solutions - 1 (Class IX)

This is the correct answer as both these statements are correct. 

The process of separating a pure substance in the form of crystals from a hot saturated solution by cooling is known as crystallization.

At a given temperature, a solution can only hold a certain amount of solute. A saturated solution is the one that contains the maximum amount of solute at a given temperature.

This is a wrong option. Blood is a colloidal solution.
This is the correct option. Milk of Magnesia is not a colloidal solution. It is a suspension.

When pressure is reduced, liquid changes to gaseous state. The water in the saturated solution becomes vapour, leaving solid salt behind. This is called vacuum drying.

Solutions generally have only two components, i.e. solute and solvent. Vinegar is a solution of acetic acid in water, i.e. in this, both solute (acetic acid) and solvent (water) are liquids and thus, it is a liquid in liquid solution. 

Tincture of iodine is obtained by dissolving iodine in alcohol. Thus, in tincture, iodine is the solute and alcohol is the solvent. Water is present as solvent in salt solution and acid is the solvent if the solution is made by dissolving some solute in acid. 

A beam of light does not scatter when it is passed through a true solution because the size of particles is less than 10^–9 m.

This is the correct option. The particles of a colloid can pass through a filter paper. Thus, a colloid cannot be separated by filtration.

This is the correct option. Sol is a colloid in which tiny solid particles are dispersed in a liquid medium. Solid sol is a colloid in which solid particles are dispersed in a solid medium. Aerosol is a colloid in which a solid or a liquid is dispersed in a gas.

Brownian motion (named after the botanist Robert Brown) or pedesis is the presumably random drifting of particles suspended in a fluid (a liquid or a gas) or the mathematical model used to describe such random movements, which is often called particle theory.

A true solution is a homogeneous mixture of two or more chemically non–reacting substances whose composition can be varied with certain limits. Vinegar is a solution of acetic acid in water, i.e. in this, both solute (acetic acid) and solvent (water) are liquids. Thus, it is liquid in liquid solution. Salt solution is an example of solid in liquid solution as in it, salt (solid) is dissolved in water (liquid). Soft drink (i.e. CO₂ dissolved in water) is gas in liquid solution as in this, gaseous solute (CO₂) is dissolved in liquid solvent (water). Air is an example of gas in gas solution. 

A true solution is a homogeneous mixture of two or more chemically non-reacting substances whose composition can be varied within limits.
A mixture is said to be a true solution if it satisfies the following two conditions:
(i) The components of the mixture should be non–reacting.
(ii) The mixture should be homogeneous.
Steel is an alloy (homogeneous mixture of two or more metals) of iron 99.95% and carbon 0.05%. Thus, it is a true solution of solid and solid. Iron is not a mixture. It is an element made up of only one type of atom. Butter and gemstones are colloids (heterogeneous mixtures in which particle size is 1-100 nm). 

The correct answer is (2), because the particle size in colloidal solution is 1 nm - 1000 nm.

More solute can be dissolved in a saturated solution by heating the solution.