chemistry MCQs - 11th class Chapter 02 Mcqs

1

The science of chemical characterization is known as?

A

Organic Chemistry

B

Physical Chemistry

C

Analytical Chemistry

D

Inorganic Chemistry

2

A complete chemical characterization includes which types of analyses?

A

Physical and Chemical

B

Qualitative and Quantitative

C

Organic and Inorganic

D

Structural and Functional

3

Which type of analysis deals with the identification of elements in a compound?

A

Quantitative Analysis

B

Volumetric Analysis

C

Qualitative Analysis

D

Gravimetric Analysis

4

The process used to separate insoluble particles from liquids is called?

A

Crystallization

B

Sublimation

C

Solvent Extraction

D

Filtration

5

What is the recommended size for a filter paper in a funnel?

A

It should be one-fourth to one-half full of precipitate

B

It should be completely full of precipitate

C

It should be less than one-fourth full of precipitate

D

The size does not matter

6

For a smooth filtration process, the stem of the funnel should be?

A

Continuously empty

B

Continuously full of liquid

C

Partially filled

D

Removed periodically

7

To prevent splashing, where should the tip of the funnel stem touch?

A

The bottom of the beaker

B

The side of the beaker

C

The surface of the liquid

D

It should not touch the beaker

8

The rate of filtration can be significantly increased by using?

A

A smaller funnel

B

A heated solution

C

A fluted filter paper

D

A thicker filter paper

9

Which crucible has a perforated bottom covered with paper pulp or filter paper?

A

Sintered glass crucible

B

Gooch crucible

C

Platinum crucible

D

Porcelain crucible

10

A Gooch crucible with an asbestos mat is used to filter solutions like concentrated HCl because they?

A

Are highly volatile

B

Are colorless

C

React with paper

D

Have low density

11

Which crucible has a porous glass disc sealed into its bottom?

A

Gooch crucible

B

Evaporating dish

C

Crucible with lid

D

Sintered glass crucible

12

What is the basic principle of crystallization?

A

Solute is insoluble at high temperature and soluble at low temperature

B

Solute is soluble in a solvent at high temperature and separates as crystals on cooling

C

The solvent and solute react chemically

D

Impurities crystallize first

13

Which of the following is NOT a feature of an ideal solvent for crystallization?

A

It should dissolve a large amount of substance at its boiling point

B

It should be expensive

C

It should not react chemically with the solute

D

It should be safe to use

14

What is used for heating if the solvent for crystallization is inflammable?

A

Direct flame

B

Induction heater

C

Water bath

D

Oven

15

Why is a hot saturated solution filtered through a fluted filter paper?

A

To cool the solution quickly

B

To add impurities

C

To avoid premature crystallization of the solute

D

To dissolve more solute

16

Slow cooling of a hot filtered solution yields?

A

Small sized crystals

B

Medium sized crystals

C

Bigger crystals

D

No crystals

17

Bigger crystals obtained from slow cooling are likely to include?

A

Pure solute only

B

A considerable amount of solvent and impurities

C

No solvent

D

Only pure solvent

18

What equipment is used to filter the mixture of crystals and mother liquor?

A

A regular funnel

B

A separating funnel

C

A Gooch crucible with a vacuum pump

D

A beaker

19

What is the mother liquor?

A

The pure solvent used for crystallization

B

The solid crystals formed

C

The crude substance before crystallization

D

The residual liquid left after crystallization

20

A safe and reliable method for drying crystals is using a?

A

Bunsen burner

B

Vacuum desiccator

C

Microwave oven

D

Fold of filter paper

21

Which substance is commonly used to decolorize a crude product?

A

Animal charcoal

B

Silica gel

C

Calcium chloride

D

Sodium chloride

22

The process where a solid turns directly into vapor upon heating is called?

A

Evaporation

B

Melting

C

Sublimation

D

Condensation

23

Which of the following solids can be purified by sublimation?

A

Sodium chloride

B

Sugar

C

Sand

D

Naphthalene

24

In sublimation, where does the pure solid deposit?

A

On the bottom of the watch-glass

B

On the sand bath

C

On the inner side of the inverted funnel

D

Outside the funnel

25

What is the principle of solvent extraction?

A

A solute separates from a solution by shaking with a miscible solvent

B

A solute separates from a solution by shaking with an immiscible solvent in which it is more soluble

C

The solute is filtered out

D

The solute is precipitated

26

Solvent extraction is an equilibrium process that follows the?

A

Law of Mass Action

B

Hess's Law

C

Distribution Law

D

Avogadro's Law

27

Repeated extractions using small portions of solvent are ___________ than a single extraction with a large volume.

A

less efficient

B

equally efficient

C

more efficient

D

not comparable

28

Solvent extraction is particularly useful when the product is?

A

Non-volatile and thermally stable

B

Volatile or thermally unstable

C

Insoluble in all solvents

D

Highly reactive

29

The word 'chromatography' originates from the Greek word 'Khromatos', meaning?

A

Color writing

B

Separation

C

Distribution

D

Movement

30

In chromatography, the two phases involved are?

A

Solid and Gas

B

Liquid and Plasma

C

Stationary and Mobile

D

Aqueous and Non-aqueous

31

In chromatography, a component with a small value of distribution coefficient 'K' will mostly remain in the?

A

Mobile phase

B

Stationary phase

C

Gaseous phase

D

Liquid phase

32

Chromatography where the stationary phase is a solid is called?

A

Partition chromatography

B

Adsorption chromatography

C

Column chromatography

D

Gas chromatography

33

Chromatography where the stationary phase is a liquid is called?

A

Adsorption chromatography

B

Thin-layer chromatography

C

Partition chromatography

D

Ion-exchange chromatography

34

In paper chromatography, the stationary phase is?

A

An organic liquid

B

A solid adsorbent like alumina

C

Water adsorbed on paper

D

The paper itself

35

In ascending paper chromatography, how does the solvent travel?

A

Downwards by gravity

B

Upwards by capillary action

C

Horizontally by pressure

D

It does not travel

36

What is a chromatogram?

A

The apparatus used for chromatography

B

The solvent used in chromatography

C

The pattern of separated components on the paper

D

The graph of K values

37

The retardation factor (Rf value) is the ratio of the distance travelled by the component to the distance travelled by the?

A

Stationary phase

B

Solvent front

C

Least soluble component

D

Most soluble component

38

If a spot on a chromatogram does not move from the original line, its Rf value is?

A

1

B

Greater than 1

C

Less than 0

D

0

39

The distribution coefficient K is the ratio of concentration of a component in the moving phase to its concentration in the?

A

Stationary phase

B

Solid phase

C

Gaseous phase

D

Solvent phase

40

How are insoluble impurities removed from a substance before crystallization?

A

By cooling the solution

B

By filtering the hot saturated solution

C

By adding more solvent

D

By using a desiccator

41

What is the purpose of washing crystals with a cold solvent after filtration?

A

To dissolve the crystals

B

To remove adhering mother-liquor

C

To heat the crystals

D

To change their color

42

Which of the following is used as a drying agent in a vacuum desiccator?

A

Water

B

Ethanol

C

Acetic acid

D

Silica gel

43

To separate products of organic synthesis from water, the most common laboratory technique is?

A

Filtration

B

Sublimation

C

Ether extraction

D

Crystallization

44

The second fold of a filter paper should be such that?

A

The edges match perfectly

B

The edges do not quite match

C

It forms a 90-degree angle

D

It is folded into four equal parts

45

For what purpose is a hot water funnel used?

A

To heat the filtrate

B

To cool the filtrate

C

To prevent premature crystallization in the funnel stem

D

To dissolve the filter paper

46

What is the result of cooling a crystallization mixture too rapidly?

A

Formation of large, pure crystals

B

Formation of small or impure crystals

C

The solute will not crystallize

D

The solvent will evaporate

47

What is the main reason for using a vacuum pump during the collection of crystals?

A

To heat the crystals

B

To dissolve the crystals

C

To drain the mother-liquor effectively

D

To wash the crystals

48

In paper chromatography, what is the mobile phase typically?

A

Water

B

A solid adsorbent

C

An organic liquid

D

The paper itself

49

The separation of components in chromatography is based on their relative __________ for the two phases.

A

sizes

B

colors

C

affinities

D

masses

50

Benzoic acid can be purified by which technique?

A

Filtration

B

Crystallization

C

Solvent Extraction

D

Sublimation