Question 1

Which of the following is an example of a pure substance?

Accepted Answer

A pure substance consists of a single type of matter and has a fixed composition. Out of the given options, iron is an element and thus a pure substance, while milk, sea water, and air are mixtures.

Question 2

A solution that contains the maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature is called:

Accepted Answer

A saturated solution is defined as a solution in which no more solute can be dissolved at that specific temperature under normal conditions.

Question 3

Which of the following is a heterogeneous mixture?

Accepted Answer

A heterogeneous mixture has non-uniform composition throughout. Soda water, sugar solution, and air are homogeneous, whereas chalk in water forms a heterogeneous suspension.

Question 4

The scattering of a beam of light by colloidal particles is known as:

Accepted Answer

The Tyndall effect is the phenomenon where light is scattered by particles in a colloid or in a very fine suspension, making the path of the beam visible.

Question 5

Which method is best suited for separating a mixture of two miscible liquids whose boiling points differ by 25°C or more?

Accepted Answer

Simple distillation is used for the separation of components of a mixture containing two miscible liquids that boil without decomposition and have sufficient difference in their boiling points (usually more than 25°C).

Is Matter Around Us Pure — NCERT Class 9 Science Important Questions & Revision Notes