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Suspension - class-IX

Description: suspension
Number of Questions: 24
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Tags: chemistry matter around us nature of matter is matter around us pure composition of matter matter : nature and behaviour is matter pure
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Suspension is a heterogeneous mixture in which very fine particles of a solid are dispersed in any medium (liquid or gas). Fine particles of the solid remain suspended in the medium.

  1. True

  2. False


Correct Option: A
Explanation:

A suspension is a heterogeneous mixture in which very fine particles of a solid are dispersed in any medium (liquid or gas). Fine particles of the solid remain suspended in the medium.

Following are the characteristics properties of suspensions

i) Heterogeneous nature: a suspension is a heterogeneous system.

ii) Visibility: the particles in a suspension can be seen with naked eyes or under a simple microscope.

iii) Particle Size: in a suspension, the size of the particles is of the order of 10-7 make or larger.

iv) Sedimentation: the particles in a suspension travel tendency to settle down. Very fine particles, however, remain suspended in the medium.

v) Separation by filtration: Larger particles in a suspension can be separated from the liquid or air by the filtration. 

A teacher instructed four students $A, S, C$ and $D$ to prepare a suspension of chalk in water. The students prepared suspension in the following manner:
student $'A'$ places a piece of chalk in water.
student $'S'$ places powdered chalk in water.
student $'C'$ places powdered chalk in water and then shakes the mixture vigorously.
student $'D'$ places powdered chalk in dil. $HCl$.
Which of the following students has correct way of preparation of suspension?

  1. Student A

  2. Student B

  3. Student C

  4. Student D


Correct Option: C
Explanation:

The correct option is (c).
On dissolving chalk powder in water,a suspension is obtained.The mixture is stirred for sometime to ensure the uniform dispersion of chalk powder in water.
Suspension is a heterogeneous mixture of particles from which the particles are settled down with time.Chalk powder does not dissolve in water at all.It just forms suspension in water and after some time settles down under the influence of gravity. 

Suspensions have solute particles with size less than 1 nm.

  1. True

  2. False


Correct Option: B
Explanation:

True solutions have solute particles with size less than 1 nm whereas suspensions have size more than 100 nm.
Colloids have size between 1 to 100 nm.

Suspension is a non-homogeneous mixture in which very fine particles of .................. are dispersed in .................

  1. solid/liquid, gas/solid

  2. gas, liquid

  3. solid, liquid/gas

  4. solid/liquid/gas, liquid


Correct Option: C
Explanation:

A suspension is a heterogeneous mixture in which very fine particles of a solid dispersed in any medium (liquid/gas). In any suspension, fine particles of the solid remain suspended in the medium.

Muddy pond water and smoke is an example of a:

  1. colloid

  2. suspension

  3. true solution

  4. none of the above


Correct Option: B
Explanation:

A suspension is a heterogeneous mixture in which very fine particles (about 10-5m in size) of solid are dispersed in any medium (liquid or gas). In suspension, the solute particles are visible to the naked eye, and remain suspended throughout the bulk of the medium. The Tyndall effect is observed in this mixture.

Muddy pond water, smoke coming out of a chimney, chalk-water mixture, coarse lime particles in water are examples of suspension.

_______________ contains solid particles that are sufficiently large for sedimentation.

  1. Pure substance

  2. Element

  3. Suspension

  4. Solution


Correct Option: C
Explanation:

A suspension is a heterogeneous mixture containing solid particles that are sufficiently large for sedimentation. Usually they must be larger than one micrometer.

Suspensions are different from colloid because :

  1. the particles of suspension settle

  2. the particles of suspension do not settle

  3. solvent and solute of suspension are homogenously moxed

  4. both a and c


Correct Option: A
Explanation:

Unlike colloids, suspensions will eventually settle. The suspended particles are visible under a microscope and will settle over time if left undisturbed. This distinguishes a suspension from a colloid, in which the suspended particles are smaller and do not settle. Colloids and suspensions are different from solutions, in which the solvent and solute are homogeneously mixed.

If a liquid is suspended in another liquid, it is called :

  1. emulsion

  2. aerosol

  3. colloid

  4. particulate


Correct Option: A
Explanation:

Putting two or more liquids together creates an emulsion if the liquids do not mix. If a liquid is suspended in another liquid, it is called an emulsion.

Suspensions transmit light. True or false?

  1. True

  2. False


Correct Option: B
Explanation:

Suspensions are "murky" or "opaque". They do not transmit light. Suspensions separate on standing. The mixture of particles can be separated by filtration.

A suspension of liquid droplets or fine solid particles in a gas is called :

  1. aerosol

  2. particulate

  3. both a and b

  4. colloid


Correct Option: C
Explanation:

A suspension of liquid droplets or fine solid particles in a gas is called an aerosol or particulate. In the atmosphere these consist of fine dust and soot particles, sea salt, biogenic and volcanogenic sulfates, nitrates, and cloud droplets.

Which of the following is an example of suspension?

  1. Milk

  2. Water

  3. Sand in water

  4. All of the above


Correct Option: C
Explanation:

A key characteristic of a suspension is that the solid particles will settle and separate over time if left alone. An example of a suspension is a mixture of water and sand. When mixed up, the sand will disperse throughout the water. If left alone, the sand will settle to the bottom.

Paste is:

  1. suspension of solid in a liquid

  2. mechanical dispersion of a solid in liquid

  3. colloidal solution of a solid in solid

  4. none of the above


Correct Option: A
Explanation:

Paste is suspension of solid in liquid.

Suspension is a : 

  1. compound

  2. mixture of two or more substances

  3. have only single type of particle

  4. none of above


Correct Option: B
Explanation:

Suspension is the heterogeneous mixture of two or more substances. In suspension, particles are suspended throughout in bulk and can be seen by naked eyes.

Why are suspensions not stable?

  1. Particles are very small

  2. Particles settle at the bottom

  3. Particles do not settle

  4. Particles mix homogeneously


Correct Option: B
Explanation:

When suspension is left for some time, particles get settled in bottom. Therefore, suspension is not stable.

Suspension shows Tyndall effect because of :

  1. large size of particles

  2. small size of particles

  3. their  settling down nature

  4. none of above


Correct Option: A
Explanation:

Suspension shows Tyndall effect because of their large size of particles. Particles of suspension are large enough to scatter rays of light and path of ray is visible through a suspension. 

Which of the following has liquid as a dispersing medium?

  1. Aerosol

  2. Gel

  3. Foam

  4. Cranberry glass


Correct Option: C
Explanation:

Mixtures are called foam when liquid is present as dispersing medium and gas is dispersed medium. For example, shaving cream, soap bubbles, etc.

A suspension of liquid droplets or fine solid particles in a gas is called as :

  1. aerosol

  2. foam

  3. emulsion

  4. gel


Correct Option: A
Explanation:

A suspension of liquid droplets or fine solid particles in a gas is called an aerosol or particulate. Aerosol is of two types: liquid aerosol and solid aerosol.

Which of the following is intermediate between suspension and solution?

  1. Mixture

  2. Colloid

  3. Element

  4. Solvent


Correct Option: B
Explanation:

Colloidal solutions are heterogeneous mixture of two or more substances. They appear homogeneous. The size of colloids is between the size of particles of solution and suspension, i.e., between 1 nanometer to 1000 nanometer.

Apparatus used to sediment particles in supension is : 

  1. centrifuge

  2. barometer

  3. balance

  4. calorimeter

  5. battery


Correct Option: A
Explanation:

Apparatus used to sediment particles in supension is centrifuge.
Calorimeter is used to measure the heat absorbed or released by a reaction.
Barometer is used to measure pressure.
Balance is used to measure weight of a substance.
Battery is used to provide electricity.

Smog is an example of:

  1. ice dispersed in air

  2. water dispersed in air

  3. smoke dispersed in air

  4. smoke and water dispersed in air


Correct Option: D
Explanation:

Smog is a colloidal solution in which the dispersed phase is solid and dispersion medium is gas along with some water droplets dispersed into the air.

Match the List-I (Colloidal dispersion) with List-II (Nature of the dispersion) and select the correct answer using the codes given below the lists:

Lits-I(Cooloidal dispersion) List-II(Nature of dispersion)
A. Milk 1. Solid in liquid
B.Clouds 2. Liquid in gas
C. Paints 3. Solid in solid
D. Jellies 4. Liquid in liquid
5. Liquid in solid
  1. A- 4; B- 2; C- 1; D- 5

  2. A- 1; B- 5; C- 3; D- 2

  3. A- 4; B- 5; C- 1; D- 2

  4. A- 1; B- 2; C- 3; D- 5


Correct Option: A
Explanation:

Milk is an emulsion of dispersed phase as a liquid in the dispersion medium as a liquid. This makes A-4, excludes Option B and D from answer choice.
Cloud is aerosol where dispersed phase is liquid and the dispersion medium is gas, Thus this makes B-2.
Paint is a solid phase in liquid medium makes C-1 and Jellies are a liquid phase in solid medium makes D-5.
Thus, option A is correct.

Compounds that lowers the surface tension between two liquids or a liquid and a solid are called surfactants.

  1. True

  2. False


Correct Option: A
Explanation:

Any molecule which helps in decreasing the surface tension that is the inter facial tension between the two surfaces of liquids or solid-liquid surface is known as surfactants. Some common examples are Soaps and Detergents.
hence the answer is true

Powder coating is a process which requires a solvent to keep the binder and filler parts in a liquid suspension form.

  1. True

  2. False


Correct Option: B
Explanation:

The main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form while liquid paints require.

Colour of colloids depends on which of the following factors?

  1. Size

  2. Mass

  3. Charge

  4. Nature


Correct Option: A
Explanation:

Colour of colloidal solution depends upon particle size.
The colour of colloidal solution changes with size of particle, eg, as particle size increases, the colour of gold solution changes from red to blue and finally to golden.

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