Practicing Class 9 Science MCQ and Class 9 Science Exploration Chapter 5 MCQ Online Test with Answers Exploring Mixtures and Their Separation daily helps in time management.
Class 9 Science Chapter 5 Exploring Mixtures and Their Separation MCQ
Exploring Mixtures and Their Separation MCQ
Class 9 Science Chapter 5 MCQ online test
Question 1.
Which one of the following may be termed as pure substance?
(a) Sodium chloride
(b) Soft drink
(c) Aerosol
(d) Soil
Answer:
(a) Sodium chloride
Question 2.
Select a compound out of the following:
(a) Air
(b) Solution
(c) Marble
(d) Stainless steel
Answer:
(c) Marble
Question 3.
Select a heterogeneous mixture out of the following:
(a) Air
(b) NaCl in water
(c) Emulsion
(d) Alloy
Answer:
(c) Emulsion
Question 4.
Which one of the following is a chemical change?
(a) Evaporation of spirit
(b) Freezing of water
(c) Heating of copper and sulphur
(d) Mixing of H2 and O2
Answer:
(c) Heating of copper and sulphur
Question 5.
A colloidal solution is:
(a) homogeneous mixture
(b) heterogeneous and transparent mixture
(c) heterogeneous mixture in which particles can be seen with naked eyes
(d) heterogeneous mixture in which particles cannot be seen with naked eyes
Answer:
(d) heterogeneous mixture in which particles cannot be seen with naked eyes
Question 6.
A mixture of ammonium chloride and sand can be separated by
(a) decantation
(b) centrifugation
(c) sublimation
(d) evaporation
Answer:
(c) sublimation
Question 7.
A mixture of sulphur and carbon disulphide is: (NCERT Exemplar)
(a) heterogeneous and shows Tyndall effect
(b) homogeneous and shows Tyndall effect
(c) heterogeneous and does not show Tyndall effect
(d) homogeneous and does not show Tyndall effect
Answer:
(d) homogeneous and does not show Tyndall effect
Question 8.
Which of the following properties is not characteristic of colloidal particles?
(a) Particles are uniformly distributed throughout the solution
(b) Particles from their solution cannot be separated by centrifugation
(c) Particles do not settle down when left undisturbed
(d) Particles scatter the beam of visible light
Answer:
(b) Particles from their solution cannot be separated by centrifugation
Question 9.
Take 5 gm each of iron filings and sulphur in a china dish. State which activity gives a compound.
(a) Mix and crush the mixture
(b) Add carbon disulphide, stir well and filter
(c) Heat strongly till red hot while mixing
(d) Separate iron filings with the help of a magnet
Answer:
(c) Heat strongly till red hot while mixing
Question 10.
Two chemical species X and Y combine together to form a product P which contains both X and Y.
X + Y → P
X and Y cannot be broken down into simple chemical reactions. Which of the following concerning X, Y and P are correct?
(i) P is a compound
(ii) X and Y are compounds
(iii) X and Y are elements
(iv) P has a fixed composition (NCERT Exemplar)
(a) (i), (ii) and (iii)
(b) (i), (ii) and (iv)
(c) (ii), (iii) and (iv)
(d) (i), (iii) and (iv)
Answer:
(d) (i), (iii) and (iv)
Question 11.
Shaving cream is a colloidal solution of
(a) gas in liquid
(b) liquid in liquid
(c) solid in liquid
(d) gas in solid
Answer:
(c) solid in liquid
Question 12.
Cloud is an example of
(a) solid dispersed in a gas
(b) liquid dispersed in a gas
(c) liquid dispersed in a solid
(d) solid dispersed in a gas
Answer:
(b) liquid dispersed in a gas
Question 13.
When a ray of light passes through a solution and it is not visible, then the solution has
(a) particles smaller than 10-9 metre in diameter
(b) particles are colloidal
(c) particles are a suspension
(d) particles of the order of 10-7 metre in diameter
Answer:
(a) particles smaller than 10-9 metre in diameter
Question 14.
The solubility of a salt in water is 20 g/100 g at 25°C. It increases 10% for every 5°C rise of temperature upto 50°C and then becomes constant. A solution of 26 g of the same salt in 100 g of water at 35°C would be
(a) saturated
(b) unsaturated
(c) translucent
(d) colloidal
Answer:
(a) saturated
Question 15.
Tick the statement which is not correct:
(a) When a beam of light is passed through a colloidal solution, the path of light gets illuminated.
(b) When an electric current is passed through a colloidal solution, colloidal particles move towards the oppositely charged electrodes.
(c) When an electric current is passed through a suspension, particles move towards the oppositely charged electrodes.
(d) When an electric current is passed through an electrolyte solution, particles move towards the oppositely charged electrodes.
Answer:
(c) When an electric current is passed through a suspension, particles move towards the oppositely charged electrodes.
Question 16.
Which of the following is a physical change?
(a) Electric current is passed through water
(b) Electric current is passed through a bulb and it glows
(c) Burning of a candle
(d) Making of curd from milk
Answer:
(a) Electric current is passed through water
Question 17.
Which of the following are homogeneous in nature? (NCERT Exemplar)
(i) Ice
(ii) Wood
(iii) Soil
(iv) Air
(a) (i) and (iii)
(b) (ii) and (iv)
(c) (i) and (iv)
(d) (iii) and (iv)
Answer:
(c) (i) and (iv)
Exploring Mixtures and Their Separation Class 9 Assertion and Reason Questions
Directions: For Questions number (i) to (ii), two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
(c) Assertion (A) is true, but Reason (R) is false.
(d) Assertion (A) is false, but Reason (R) is true.
Question 1.
Assertion (A): Colloidal solutions are homogeneous mixtures.
Reason (R): Colloidal solutions have uniform concentration.
Answer:
(d) (A) is false but (R) is true.
Question 2.
Assertion (A): Air is a homogeneous mixture.
Reason (R): Components of air can be separated by fractional distillation.
Answer:
(b) Both Assertion (A) and Reason (R) are true and Reason (R) is not the correct explanation of Assertion (A).
Exploring Mixtures and Their Separation Class 9 Fill in the Blanks
1. A mixture that has a uniform composition throughout is called a ___________ mixture, while one with non-uniform composition is called ___________.
Answer:
homogeneous, heterogeneous
2. The technique used to separate suspended solid particles from a liquid is ___________.
Answer:
filtration
3. ___________ is the process used to separate components of a mixture where one substance changes directly from solid to gas, such as ammonium chloride from salt.
Answer:
Sublimation
4. ___________ is a method used to separate dense particles from a liquid by spinning them at high speed.
Answer:
centrifugation
5. The technique of ___________ is used to separate solutes that dissolve in the same solvent.
Answer:
chromatography
6. ___________ is used to separate miscible liquids that boil without decomposition and have a large difference in their boiling points.
Answer:
Distillation
Exploring Mixtures and Their Separation Class 9 True or False
1. Salt can be separated from a salt solution by evaporation.
Answer:
True.
Evaporation separates the liquid solvent, leaving the solid solute (salt) behind.
2. In paper chromatography, the solvent level should be above the sample spot at the beginning.
Answer:
False.
The solvent must be below the spot to avoid dissolving the sample directly instead of allowing it to be carried up by capillary action.
3. Air is a heterogeneous mixture.
Answer:
False.
Clean air is a homogeneous mixture (uniform composition of gases).
4. The Tyndall Effect is observed in true solutions.
Answer:
False.
It occurs in colloids and suspensions (scattering of light), not in true solutions.
5. Separation of components helps us know what a mixture is made of.
Answer:
True.
This is a fundamental reason for studying separation techniques.
Exploring Mixtures and Their Separation Class 9 Match the Following
Question 1.
Match the following items given in Column A with that in Column B:
| Column A (Mixture) | Column B (Separation Technique) |
| 1. Oil and Water | (a) Chromatography |
| 2. Salt and Water | (b) Centrifugation |
| 3. Cream from Milk | (c) Separating Funnel |
| 4. Dyes in Black Ink | (d) Sublimation |
| 5. Camphor and Salt | (e) Evaporation |
Answer:
| Column A (Mixture) | Column B (Separation Technique) |
| 1. Oil and Water | (c) Separating Funnel |
| 2. Salt and Water | (e) Evaporation |
| 3. Cream from Milk | (b) Centrifugation |
| 4. Dyes in Black Ink | (a) Chromatography |
| 5. Camphor and Salt | (d) Sublimation |
MCQ On Exploring Mixtures and Their Separation Class 9 for Practice
Choose the correct option in the following questions:
Question 1.
Which is not correct with respect to a mixture?
(a) The components can be separated by simple physical means.
(b) They have fixed melting and boiling point.
(c) The components are not chemically combined in fixed ratio.
(d) Mixtures are also called impure substances.
Question 2.
Which of the following is a colloid?
(a) Tomato sauce
(b) Air
(c) Soil
(d) Water
Question 3.
Which one is a homogeneous mixture?
(a) Common salt + sugar
(b) Oil + water
(c) Common salt + water
(d) Iron filings + sulphur
Question 4.
The technique widely used in laboratories to separate components of blood (like RBCs and Plasma) is:
(a) Centrifugation
(b) Coagulation
(c) Distillation
(d) Sublimation
Question 5.
If a student mixes egg white with water and stirs well, what will be observed?
(a) A transparent solution is formed
(b) A translucent mixture is formed
(c) Egg white settles at the bottom.
(d) Egg white floats on the surface of water.
Assertion-Reason Questions:
Directions: For Questions number (i) to (ii), two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
(b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
(c) Assertion (A) is true, but Reason (R) is false.
(d) Assertion (A) is false, but Reason (R) is true.
Question 1.
Assertion (A): Camphor on heating below its boiling point changes directly from solid state to vapour state without passing through the liquid state. This process is called sublimation.
Reason (R): On cooling, vapours directly change back into solid without becoming a liquid. This process is called deposition.
Question 2.
Assertion (A): A suspension is a homogeneous solution in which the solute particles neither dissolve nor settle down.
Reason (R): Sulphur dissolved in carbon disulfide is a homogeneous mixture.
Fill in the Blanks:
1. A ___________ is a solid that is made up of particles arranged in a regular geometric pattern.
2. ___________ acid helps in making pure crystals by preventing unwanted reactions during crystallization.
3. The formation of cheese from milk involves coagulation in which acids like lemon juice or vinegar are used as a ___________.
4. The terms dispersed phase and dispersion medium are used in ___________.
5. The solute in 80% ethanol is ___________.
State whether the statements given below are True or False:
1. Aerated drinks like soda water (carbon dioxide and water) always form a homogeneous mixture.
2. Solubility of gases dissolved in liquids generally increases with an increase in temperature.
3. Snowflakes are crystals formed naturally when water vapour freezes in air during coagulation.
4. It is possible to separate a mixture of two miscible liquids by evaporation and obtain both the liquids.
5. Paper chromatography uses the principle of differences in interactions of the components with the solvent and the paper to separate them.
Match the Columns:
Question 1.
| Column A | Column B |
| 1. Rocket fuel | (a) Solid-solid mixture |
| 2. Smoke | (b) Tiny liquid droplets present in air |
| 3. Fog | (c) Colloid |
| 4. Egg white in water | (d) Solid particles suspended in air |
| 5. Sawdust and iron nails | (e) Mixture of hydrogen and oxygen |
Question 2.
| Column A (Name of the Alloy) | Column B (Components Present) |
| 1. Brass | (a) Iron, carbon, chromium, nickel, molybdenum |
| 2. Bronze | (b) Copper 80% and zinc 20% |
| 3. Stainless steel | (c) Copper 80% and tin 20% |