| Publisher | : Santra publication pvt. ltd. |
| Book Name | : Madhyamik Physical Science And Environment |
| Class | : 9 (Madhyamik) |
| Subject | : Physical Science |
| Chapter Name | : Separation of Component of Mixture |
Multiple Choice Questions (MCQ)
[Each of Mark-1]
Question 1
A solution of sugar in water is
- a homogeneous mixture
- a heterogeneous mixture
- separated two immiscible liquids
- none of these
Answer
a homogeneous mixture
Explanation
A solution of sugar in water is a homogeneous mixture because the sugar molecules are uniformly distributed throughout the water.
Question 2
Bronze is an example of
- solid in a solid homogeneous mixture
- solid is a solid heterogeneous mixture
- solid is a liquid homogeneous mixture
- solid in a liquid heterogeneous mixture
Answer
solid in a solid homogeneous mixture
Explanation
Bronze is an example of a solid in a solid homogeneous mixture, as it is an alloy composed of copper and tin uniformly mixed at the atomic level.
Question 3
Which one is solid in the liquid homogeneous mixture?
- gun powder
- water in sponge
- lodine in alcohol
- oil in water
Answer
Iodine in alcohol
Explanation
Iodine in alcohol is an example of a solid in a liquid homogeneous mixture, as the iodine particles are uniformly dispersed in the alcohol solvent.
Question 4
A mixture of common salt (NaCl) and NH4Cl(s) can be separated by
- magnetic separation
- mechanical picking
- sublimation
- filtration
Answer
sublimation
Explanation
The mixture of common salt (NaCl) and NH4Cl(s) can be separated by sublimation since NH4Cl sublimes directly from solid to gas leaving NaCl behind.
Question 5
Sedimentation and decantation in a method of separation suitable for
- solid in a solid homogeneous mixture
- liquid in a liquid homogeneous mixture
- solid in a liquid heterogeneous mixture
- solid in a solid heterogeneous mixture
Answer
solid in a liquid heterogeneous mixture
Explanation
Sedimentation and decantation are methods of separation suitable for separating solid in a liquid heterogeneous mixture. In this process, the solid particles settle down (sedimentation) and the clear liquid is poured off (decantation).
Question 6
Fractional distillation is used for the separation of a mixture
- solid in the liquid mixture
- liquid in solid
- liquid-liquid immiscible
- liquid-liquid miscible
Answer
liquid-liquid miscible
Explanation
Fractional distillation is used for the separation of a liquid-liquid miscible mixture, where the components have different boiling points and can be vaporized and condensed at different temperatures.
Question 7
The use of a separatory funnel
- depends on volume ratio of two liquids
- depends on density difference of two liquids
- does not depends on miscibility of liquids
- depends on temperature
Answer
depends on the density difference of two liquids
Explanation
The use of a separatory funnel depends on the density difference of two liquids, as it allows for the separation based on the principle of liquid-liquid phase separation.
Question 8
The use of fractional distillation depends on
- volume ratio of liquids
- density ratio of liquids
- difference in boiling points of the liquids
- on colour of the liquids
Answer
the difference in boiling points of the liquids
Explanation
The use of fractional distillation depends on the difference in boiling points of the liquids being separated. It enables the separation based on their vaporization and condensation temperatures.
Question 9
Which one is not a product of the fractional distillation of crude petroleum?
- petrol
- diesel
- ethanol
- kerosene
Answer
Ethanol
Explanation
Ethanol is not a direct product of the fractional distillation of crude petroleum. It is typically produced through fermentation or other processes involving biomass or grains.
Question 10
Water boils at 100°C under the pressure of
- 760 cm of Hg
- 76 cm of Hg
- 7.6 mm of Hg
- 7.6 cm of Hg
Answer
760 cm of Hg
Explanation
Water boils at 100°C under the pressure of 760 mm of Hg (mercury), which is equivalent to 760 cm of Hg.
Answer in one word or in one sentence
[Each of Mark-1]
Questions 1
What is a mixture?
Answer
A mixture is a combination of two or more substances that are physically combined but not chemically bonded together.
Questions 2
Which component is present in a higher percentage in brass ?
Answer
The component present in a higher percentage in brass is copper (typically ranging from 55% to 90% in composition).
Questions 3
Name an alloy of aluminium.
Answer
An alloy of aluminum is called “duralumin.”
Questions 4
What separation method would you suggest for separation between (i) kerosene and water, (ii) two liquids of different densities.
Answer
(i) separatory funnel.
(ii) fractional distillation.
Questions 5
Give an example of a gas in gas (i) heterogeneous, (ii) homogeneous mixture.
Answer
- air is a homogeneous mixture
- Water vapour (think clouds) is a heterogeneous mixture
Questions 6
What is sublimation ?
Answer
Sublimation is the process in which a substance transitions directly from a solid to a gas phase without passing through the liquid phase.
Questions 7
Give an example of using the method of sublimation.
Answer
An example of sublimation is when solid dry ice (frozen carbon dioxide) turns directly into gas without melting into a liquid.
Questions 8
What is (i) sedimentation, (ii) evaporation, (iii) boiling, (iv) filtration ?
Answer
- Sedimentation: The process where solid particles settle down at the bottom of a liquid due to gravity.
- Evaporation: The process of converting a liquid into a gas by heating or exposing it to heat.
- Boiling: The process in which a liquid turns into a vapor state when heated to its boiling point.
- Filtration: The method of separating solid particles from a liquid or gas by passing it through a porous material called a filter.
Questions 9
What is (i) alloy, (ii) distillate, (iii) filtrate, (iv) sediment.
Answer
- Alloy: A mixture of two or more metals or metals with a non-metal, typically formed by melting and blending them together.
- Distillate: The liquid collected or condensed during the process of distillation, where a liquid mixture is heated and the vapours are condensed back into liquid form.
- Filtrate: The liquid that passes through a filter during the process of filtration, separating it from the solid particles.
- Sediment: Solid particles that settle down at the bottom of a liquid due to gravity, forming a layer or deposit.
Questions 10
What is a separatory funnel ?
Answer
A separatory funnel is a laboratory tool used for separating immiscible liquids of different densities by allowing them to settle into distinct layers for easy separation.
Short answer type questions
[Each of Mark-2 or 3]
Questions 1
Name the physical process which is applied to separate acetone and ethyl alcohol. Why would you apply this method?
Answer
The physical process applied to separate acetone and ethyl alcohol is “fractional distillation.” This method is used because acetone and ethyl alcohol have different boiling points, allowing them to vaporize and condense at different temperatures for separation.
Questions 2
Name the process by which the components of crude oil may be separated. Name three such components.
Answer
The process by which the components of crude oil may be separated is called “fractional distillation.” Three components that can be separated from crude oil are gasoline, diesel fuel, and kerosene.
Questions 3
Differentiate between ordinary distillation and fractional distillation processes.
Answer
- Ordinary distillation is used when the components of a mixture have significantly different boiling points, while fractional distillation is used for mixtures with closer boiling points.
- Fractional distillation uses a fractionating column to achieve better separation by providing multiple vaporization and condensation stages, while ordinary distillation does not employ such a column.
- Fractional distillation allows for the separation of a mixture into more precise fractions, while ordinary distillation generally results in a less refined separation.
Questions 4
Give a sketch to represent fractional distillation. Mention one industrial use of this process.
Answer
One industrial use of fractional distillation is in the refining of crude oil to produce different petroleum products such as gasoline, diesel fuel, and jet fuel.
Questions 5
Explain the working principle for fractional distillation mentioning the importance of boiling points.
Answer
The working principle of fractional distillation relies on the fact that different components in a liquid mixture have different boiling points. Here’s how it works:
Fractional distillation works by heating a mixture of liquids to separate them based on their different boiling points. The liquid with the lowest boiling point evaporates first and rises in the distillation (Fractionating) column, while the one with the higher boiling point remains in liquid form. This separation happens because substances with different boiling points condense at different heights in the column, allowing for efficient separation based on boiling point differences.
