Chemistry Tricks Of Physical and Chemical Changes & Elements, Mixtures and Compounds for NDA

Physical and Chemical Changes

Q 2816180070







Column IColumn II
(A) Formation of cloud (1)Dissolution of salt
(B) Formation of acid rain (2) Flusting
(C) Corrosion of iron (3) Chemical change
(D) Physical process (4) Physical change


(A)

`A → 4 , B →3 , C → 2 , D →1`

(B)

`A → 1 , B →2 , C → 3 , D →4`

(C)

`A → 1 , B →3 , C → 4 , D →2`

(D)

`A → 4 , B →2 , C → 3 , D →1`

Solution:


Correct Answer is `=>` (A) `A → 4 , B →3 , C → 2 , D →1`
Q 2806178978

Which of the following changes are chemical changes?
I. Burning of candle
II. Breaking of chalk
III. Melting of wax
IV. Formation of water from hydrogen and oxygen.

(A)

I and II

(B)

II and Ill

(C)

Ill and IV

(D)

I and IV

Solution:


Correct Answer is `=>` (D) I and IV
Q 2876178976

Which of the following processes responsible for chemical change?
I. Electrolysis
II. Sublimation
III. Corrosion
IV. Decomposition


(A)

I and II

(B)

II and Ill

(C)

Ill and IV

(D)

I, Ill and IV

Solution:


Correct Answer is `=>` (D) I, Ill and IV
Q 2866178975

Which of the following processes related to chemical change?
I. Movement of free electrons in copper wire.
II. Electric current passes through copper wire.
III. Electric current passes through `NaCl` aqueous solution.

(A)

I and II

(B)

II and Ill

(C)

I and Ill

(D)

Ill only

Solution:


Correct Answer is `=>` (D) Ill only
Q 2846178973

Which of the following represent a chemical change?
I. Magnetisation of iron
II. Condensation of liquid
III. Burning of fuel
IV. Rusting of iron

(A)

I and II

(B)

II and Ill

(C)

Ill and IV

(D)

I and IV

Solution:


Correct Answer is `=>` (C) Ill and IV
Q 2836178972

Which of the following processes related to physical change?
I. Salt dissolved in water.
II. Dissociation of salt in water
III. Decomposition of salt by electrolysis

(A)

I and II

(B)

II and Ill

(C)

I and Ill

(D)

All of these

Solution:


Correct Answer is `=>` (A) I and II
Q 2816178970

Statement I : Making of soda water by dissolving carbon dioxide in water is a chemical change.
Statement II : A change in which chemical composition remains same is called physical change.

(A)

Both the statements are true and Statement II is the correct explanation of Statement I

(B)

Both the statements are true but Statement II is not the correct explanation of Statement I.

(C)

Statement I is true, but Statement II is false

(D)

Statement I is false, but Statement II is true.

Solution:


Correct Answer is `=>` (D) Statement I is false, but Statement II is true.
Q 2816078879

Statement I : Emission of light from stars is a chemical change.
Statement II : Source of light from stars is nuclear fission reactions.

(A)

Both the statements are true and Statement II is the correct explanation of Statement I

(B)

Both the statements are true but Statement II is not the correct explanation of Statement I.

(C)

Statement I is true, but Statement II is false

(D)

Statement I is false, but Statement II is true.

Solution:


Correct Answer is `=>` (C) Statement I is true, but Statement II is false
Q 2806078878

Statement I : Sublimation of `NH_4Cl` is a chemical change.

Statement II : Sublimation is a phenomenon in which a solid on heating directly changes into gas without changing to liquid.

(A)

Both the statements are true and Statement II is the correct explanation of Statement I

(B)

Both the statements are true but Statement II is not the correct explanation of Statement I.

(C)

Statement I is true, but Statement II is false

(D)

Statement I is false, but Statement II is true.

Solution:


Correct Answer is `=>` (D) Statement I is false, but Statement II is true.
Q 2876078876

Which of the following represent both physical and chemical change?
I. Burning of candle
II. Burning of methane
III. Decomposition of salt Codes

(A)

I and II

(B)

II and Ill

(C)

I and Ill

(D)

Only I

Solution:


Correct Answer is `=>` (D) Only I
Q 2866078875

Which of the following represent a physical change?
I. Cutting of carrot into pieces.
II. Separation of iron and sulphur from their mixture
III. Formation of salt from sea-water Codes

(A)

I and II

(B)

II and Ill

(C)

I and Ill

(D)

All of these

Solution:


Correct Answer is `=>` (D) All of these
Q 2846078873

Combustion of a candle is a/an

(A)

physical change

(B)

reduction reaction

(C)

endothermic reaction

(D)

exothermic reaction

Solution:


Correct Answer is `=>` (D) exothermic reaction
Q 2836078872

An endothermic reaction is accompanied by

(A)

evolution of light and water

(B)

evolution of heat

(C)

absorption of heat

(D)

None of the above

Solution:


Correct Answer is `=>` (C) absorption of heat
Q 2826078871

Heating of a substance results in

(A)

a physical change

(B)

a chemical change

(C)

a physical or a chemical change

(D)

None of the above

Solution:


Correct Answer is `=>` (C) a physical or a chemical change
Q 2816078870

Any change in matter that results in the disappearance of one or more substances and the appearance of one or more substances, each having its own set of intensive properties is known as

(A)

extrinsic change

(B)

intrinsic change

(C)

physical change

(D)

chemical change

Solution:


Correct Answer is `=>` (D) chemical change
Q 2816878779

Which among the following is a chemical change?

(A)

A wet towel dries in the sun

(B)

Lemon juice added to tea causing its colour to change

(C)

Hot air rises over a radiator

(D)

Coffee is brewed by passing steam through ground coffee

Solution:


Correct Answer is `=>` (D) Coffee is brewed by passing steam through ground coffee
Q 2806878778

Which one among the following is a chemical process?

(A)

Distillation of sea (salty) water

(B)

Crystallisation of impure salt (`NaCl`)

(C)

Production of iodine (`1_2` ) from seaweeds

(D)

Sublimation of iodine `(I_2)`

Solution:


Correct Answer is `=>` (C) Production of iodine (`1_2` ) from seaweeds
Q 2876878776

Which of the following substances undergo chemical changes on heating?

(A)

Sodium chloride

(B)

Silica

(C)

Lead nitrate

(D)

Platinum wire

Solution:


Correct Answer is `=>` (C) Lead nitrate
Q 2866878775

Which of the following is always accompanied during a chemical change?

(A)

Evolution of light

(B)

Evolution or absorption of heat

(C)

Evolution of heat only

(D)

Absorption of heat only

Solution:


Correct Answer is `=>` (B) Evolution or absorption of heat
Q 2856878774

Which of the following is a chemical change?

(A)

Evaporation

(B)

Dissolution

(C)

Sublimation

(D)

Precipitation

Solution:


Correct Answer is `=>` (D) Precipitation
Q 2846878773

Which of the following is a chemical change?

(A)

Heating of iron to red hot

(B)

Magnetisation of iron piece

(C)

Rusting of iron rod

(D)

All of the above

Solution:


Correct Answer is `=>` (C) Rusting of iron rod
Q 2836878772

Which of the following is a physical change?

(A)

Formation of curd

(B)

Burning of candle

(C)

Rusting of iron rod

(D)

Heating of copper wire by electricity

Solution:


Correct Answer is `=>` (D) Heating of copper wire by electricity
Q 2816878770

Which of the following is a physical change?

(A)

Oxidation

(B)

Reduction

(C)

Both (a) and (b)

(D)

None of these

Solution:


Correct Answer is `=>` (D) None of these
Q 2816778679

Which of the following is not a chemical change?

(A)

Combustion of fuel

(B)

Electrolysis of acidified water

(C)

Oxidation reaction of cells at anode

(D)

Glowing of a platinum wire

Solution:


Correct Answer is `=>` (D) Glowing of a platinum wire
Q 2806778678

Which of the following is a true statement about the physical change?

(A)

Physical changes are temporary changes and can be reversed

(B)

During physical changes tile composition of constituents molecule changes.

(C)

Energy is absorbed or released during a physical change

(D)

Identity of tile substance is lost after tile physical change

Solution:


Correct Answer is `=>` (A) Physical changes are temporary changes and can be reversed

Elements, Mixtures and Compounds

Q 1713701640

Which of the following statements about a compound is incorrect?
NCERT Exemplar
(A)

A molecule of a compound has atoms of different elements

(B)

A compound cannot be separated into its constituent elements by physical methods of separation

(C)

A compound retains the physical properties of its constituent elements

(D)

The ratio of atoms of different elements in a compound is fixed

Solution:

A compound is a pure substance containing two or more than two elements combined
together in a fixed proportion by mass and which can be decomposed into its
constituent elements by suitable chemical methods.
Further, the properties of a compound are quite different from the properties of
constituent elements. e.g., water is a compound containing hydrogen and oxygen
combined together in a fixed proportionation. But the properties of water are completely
different from its constituents, hydrogen and oxygen.
Correct Answer is `=>` (C) A compound retains the physical properties of its constituent elements
Q 2886891777

Statement l : The formation of a mixture neither requires nor releases heat, light and electricity.
Statement II : A mixture is a combination of two or more pure substances that are not chemically united.

(A)

Both the statements are true and Statement II is the correct explanation of Statement I.

(B)

Both the statements are true but Statement II is not the correct explanation of Statement I.

(C)

Statement I is true but Statement II is false.

(D)

Statement I is false, but Statement II is true.

Solution:


Correct Answer is `=>` (A) Both the statements are true and Statement II is the correct explanation of Statement I.
Q 2836891772

Consider the following statements.
I. Pure milk is mixture.
II. Bronze is solution.
III. Brine is solution
IV. Graphite is pure substance

(A)

I and II

(B)

II and Ill

(C)

III and IV

(D)

All of the above

Solution:


Correct Answer is `=>` (D) All of the above
Q 2886791677

Consider the following statements.
I. Brass is a solid solution.
II. Sand and water is a solution.
III. Salt and sand is homogeneous mixture.
IV. Air is a solution.

(A)

I and II

(B)

II and Ill

(C)

Ill and IV

(D)

I and IV

Solution:


Correct Answer is `=>` (D) I and IV
Q 2876791676

Consider the following statements.
I. Aqueous solution of `NaCl` is a homogeneous mixture.
II. Alloy is solid solution.
III. Milk is a mixture.

(A)

I and II

(B)

II and Ill

(C)

Ill and IV

(D)

I and IV

Solution:


Correct Answer is `=>` (D) I and IV
Q 2866791675

Match List I with List II and select the correct answer from the codes given below the lists








List IList II
(A) Bronze (1) Solution
(B) `CO_2` (2) Compound
(C) Mixture of oil
and water
(2) Heterogeneous
mixture
(D) Mixture of water
and alcohol
(4) Solid solution


(A)

`A → 4 , B →2 , C → 3 , D →1`

(B)

`A → 1 , B → 2 , C → 3 , D → 4`

(C)

`A → 2 , B → 1 , C → 4 , D → 3`

(D)

`A → 2 , B → 4 , C → 3 , D → 1`

Solution:


Correct Answer is `=>` (A) `A → 4 , B →2 , C → 3 , D →1`
Q 2846791673

False statement is

(A)

germanium is a semi-conductor

(B)

steel is an alloy

(C)

graphite is an element

(D)

the fundamental unit in silicates is `Si_2O_3`

Solution:


Correct Answer is `=>` (D) the fundamental unit in silicates is `Si_2O_3`
Q 2836791672

Which of the following is a compound?

(A)

Rhombic sulphur

(B)

Marble

(C)

Diamond

(D)

Quick silver

Solution:


Correct Answer is `=>` (B) Marble
Q 2836591472

First organic compound which was prepared in laboratory is

(A)

methane

(B)

urea

(C)

formaldehyde

(D)

water

Solution:


Correct Answer is `=>` (B) urea
Q 2806691578

Which one of the following is a compound?

(A)

Glass

(B)

Water gas

(C)

CNG

(D)

Plaster of Paris

Solution:


Correct Answer is `=>` (D) Plaster of Paris
Q 2856691574

Who prepared the first organic compound in laboratory?

(A)

Dalton

(B)

Wohler

(C)

Kolbe

(D)

Berthelot

Solution:


Correct Answer is `=>` (B) Wohler
Q 2846591473

Barium carbonate is a/an

(A)

compound

(B)

mixture

(C)

element

(D)

alloy

Solution:


Correct Answer is `=>` (A) compound
Q 2886491377

Which one of the following is the most abundant compound?

(A)

`H_2O`

(B)

`SiO_2`

(C)

`Al_2O_3`

(D)

Air

Solution:


Correct Answer is `=>` (A) `H_2O`
Q 2856491374

Water is a Compound because

(A)

it exists as solid, liquid or gas

(B)

it contains hydrogen and oxygen

(C)

it contains two different elements joined by chemical bonds

(D)

it can be split up into simpler substance by chemical means

Solution:


Correct Answer is `=>` (C) it contains two different elements joined by chemical bonds
Q 2816480370

LPG (Liquefied petroleum gas) is a

(A)

mixture

(B)

compound

(C)

element

(D)

None of these

Solution:


Correct Answer is `=>` (A) mixture
Q 2886380277

Which of the following is neither an element nor a compound?

(A)

Air

(B)

Water

(C)

Mercury

(D)

Sodium chloride

Solution:


Correct Answer is `=>` (A) Air
Q 2876380276

Match list I with list II and select the correct answer from the codes given below the lists.








List I (Element) I List II (Symbol)
(A) Thallium (1) Tm
(B) Thorium (2) TI
(C) Thulium (3) Tb
(D) Terbium (4) Th


(A)

`A -> 2, B -> 4 , C -> 3, D -> 1`

(B)

`A → 2 , B → 4 , C → 1 , D → 3`

(C)

`A → 1 , B → 3 , C → 2 , D → 4`

(D)

`A → 4 , B → 2 , C → 1 , D → 3`

Solution:


Correct Answer is `=>` (B) `A → 2 , B → 4 , C → 1 , D → 3`
Q 2826380271

Magnesium is present in

(A)

haemoglobin

(B)

chlorophyll

(C)

vitamin `B_(12)`

(D)

ascorbic acid

Solution:


Correct Answer is `=>` (B) chlorophyll
Q 2816380270

metals heavier than lead

(A)

cast iron

(B)

pig iron

(C)

steel

(D)

wrought iron

Solution:


Correct Answer is `=>` (D) wrought iron
Q 2886280177

Metalloids are

(A)

alloys of alkali metals with other metals

(B)

colloids of metals

(C)

element having some properties of metals and non-metals

(D)

metals heavier than lead

Solution:


Correct Answer is `=>` (C) element having some properties of metals and non-metals
Q 2836280172

Which one among the following is an element?

(A)

Graphite

(B)

Glass

(C)

Brass

(D)

Steel

Solution:


Correct Answer is `=>` (A) Graphite
Q 2826280171

Which one of the following is not a mixture?

(A)

Air

(B)

Mercury

(C)

Milk

(D)

Cement

Solution:


Correct Answer is `=>` (B) Mercury
Q 2806180078

An element which is not found in nature is

(A)

Pt

(B)

K

(C)

Zn

(D)

Pu

Solution:


Correct Answer is `=>` (D) Pu
Q 2886180077

Which one of the following is most abundant metallic element?

(A)

Aluminium

(B)

iron

(C)

Gold

(D)

Silver

Solution:


Correct Answer is `=>` (A) Aluminium
Q 2876180076

The most abundant gas in the atmosphere is

(A)

nitrogen

(B)

oxygen

(C)

helium

(D)

carbon dioxide

Solution:


Correct Answer is `=>` (A) nitrogen

Separation of Mixture

Q 1729267111


NCERT Exemplar

Assertion : (A) Components of a mixture of red and blue inks can be separated by distributing the components between stationary and mobile phases in paper chromatography

Reason : (R) The coloured components of inks migrate at different rates because paper selectively retains different components according to the difference in their partition between the two phases

(A) Both A and R individually true and R is the correct explanation of A
(B) Both A and R are individually true but R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true
Solution:

Both A and Rare correct and R is the correct explanation of A
In paper chromatograplly, a chromatography paper is used. It contains water in it,which
acts as the stationary phase. A strip oi chromatography paper spotted at the base with
ink is suspended in a suitable solvent. Solvent acts as the mobile phase.
The solvent rises up tile paper by capillary action and flows over the spot. The paper
selectively retains different components according to their differing partition in two
phases.
Hence, components of ink will migrate at different rates and are separated.
Correct Answer is `=>` (A)
Q 1779745616


NCERT Exemplar

Assertion : (A) Simple distillation can help in separating a mixture of propan-1-ol (boiling point `97^0C`) and propanone (boiling point `56^0C`).

Reason : Liquids with a difference of more than `20^0` in their boiling points can be separated by simple distillation.

(A) Both A and R individually true and R is the correct explanation of A
(B) Both A and R are individually true but R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true
Solution:

Both A and R are correct and R is the correct explanation of A.
Simple distillation can be used to Separate a mixture of two liquids which do not react
and have point difference of more than `20^0C`. Hence, a mixture of propan-1-ol
and propanone can be separated.
Correct Answer is `=>` (A)
Q 1789145017








Column IColumn II
(A) Two solids which have different solubilities in a
solvent and which do not undergo reaction
when dissolved in it
(1) Steam distillation
(B) Liquid that decomposes at its boiling point (2)
(C) Steam volatile liquid (3) Simple distillation
(D) Two liquids which have boiling points close to
each other
(4) Distillation under reduced
pressure
(E) two liquids with large difference in boiling points (5) Crystallisation

NCERT Exemplar

(This question may have multiple correct answers)

(A) `Arightarrow(5)`
(B) `Brightarrow(4)`
(C) `Crightarrow(1)`
(D) `Drightarrow(2)` `Erightarrow(3)`
Solution:


Correct Answer is `=>` (A)
Q 1709212118

The fragrance of flowers is due to the presence of some steam volatile
organic compounds called essential oils. These are generally insoluble in
water at room temperature but are miscible with water vapour in vapour
phase. A suitable method for the extraction of these oils from the flowers
is
NCERT Exemplar
(A)

distillation

(B)

crystallisation

(C)

distillation under reduced pressure

(D)

steam distillation

Solution:

As we know, essential oils are insoluble in water and have high vapour-pressure at
373K but are miscible with water-vapour in vapour phase, it means these are steam
volatile. Hence, steam distillation technique is used for the extraction of essential oils.
Correct Answer is `=>` (D) steam distillation
Q 1729312211

During hearing of a court case, the judge suspected that some changes in
the documents had been carried out. He asked the forensic department to
check the ink used at two different places. According to you which
technique can give the best results?
NCERT Exemplar
(A)

Column chromatography

(B)

Solvent extraction

(C)

Distillation

(D)

Thin layer chromatography

Solution:

Thin layer chromatography (TLC) is an another type of adsorption which involves
separation of substances of a mixture over a thin layer of an adsorbent coated on a
glass plate.
A thin layer of an adsorbent is spread over a glass plate and glass plate is placed in an
eluant. As eluant rises, components of the mixture move up along with the eluant to
different distances depending on their degree of adsorption and separation takes
place. Therefore, this TLC technique will give best results in identifying the different
types of ink used at different places in the documents.
Correct Answer is `=>` (D) Thin layer chromatography
Q 1939091812

Name a suitable technique of separation oft he
components from a mixture of calcium sulphate
and camphor.
Class 11 Exercise 12 Q.No. 27
Solution:

A mixture of camphor and `CaSO_4` can be
separated by the following methods:

(i) Camphor is a sublimable solid while `CaSO_4`
is not, therefore, sublimation of mixture
gives camphor on the sides offunnel while
`CaSO_4` is left in the china dish.

(ii) Camphor is soluble in organic solvents like
`CHCl_3,C Cl_4` etc while `CaSO_4` is not.
Therefore, when the mixture is shaken with
the solvent, camphor goes into solution
while `CaSO_4` remains as residue. It is
filtered and evaporation of solvent gives
camphor.
Q 2856091874

Statement I : o and p-nitrophenol can be separated by steam distillation.
Statement II : o-nitrophenol contains inter molecular H-bonding while p-niirophenol exists as associated molecules.

(A)

Both the statements are true and Statement II is the correct explanation of Statement I

(B)

Both the statements are true but Statement II is not the correct explanation of Statement I.

(C)

Statement I is true, but Statement II is false

(D)

Statement I is false, but Statement II is true.

Solution:


Correct Answer is `=>` (A) Both the statements are true and Statement II is the correct explanation of Statement I
Q 2826091871

Statement I : In paper chromatography. both the fixed phase and mobile phase are liquids.
Statement II : Distribution of the solute between the two liquids makes the separation possible.

(A)

Both the statements are true and Statement II is the correct explanation of Statement I

(B)

Both the statements are true but Statement II is not the correct explanation of Statement I.

(C)

Statement I is true, but Statement II is false

(D)

Statement I is false, but Statement II is true.

Solution:


Correct Answer is `=>` (A) Both the statements are true and Statement II is the correct explanation of Statement I
Q 2806391278

Which one of the following is not separated by sublimation?

(A)

Corrosive sublimate

(B)

Calomel

(C)

`CuSO_4`

(D)

both (b) and (c).

Solution:


Correct Answer is `=>` (D) both (b) and (c).
Q 2876391276

`I_2` in water is extracted with the help of

(A)

Chloroform

(B)

carbon tetrachloride

(C)

carbon disulphide

(D)

All of the above

Solution:


Correct Answer is `=>` (D) All of the above
Q 2846391273

Pure water is obtained from sea water by

(A)

filtration

(B)

distillatior

(C)

evaporation

(D)

All of the above

Solution:


Correct Answer is `=>` (B) distillatior
Q 2826391271

Solution of `CaCO_3` in water forms a

(A)

homogeneous mixture

(B)

heterogeneous mixture

(C)

azeotropic mixture

(D)

None of the above

Solution:


Correct Answer is `=>` (B) heterogeneous mixture
Q 2806291178

Dialysis is used for the purification of

(A)

suspensions

(B)

true solut ons

(C)

homogeneous mixture

(D)

colloidal solution

Solution:


Correct Answer is `=>` (D) colloidal solution
Q 2886291177

During fractional distillation, the substance with

(A)

lower boiling point is obtained first

(B)

higher boiling point is obtained first

(C)

higher molecular weight is obtained first

(D)

lowest melting point is obtained first

Solution:


Correct Answer is `=>` (B) higher boiling point is obtained first
Q 2876291176

In column chromatography, the substance obtained in the top most region of column is

(A)

maximum adsorbed

(B)

minimum adsorbed

(C)

have maximum rate of diffusion

(D)

have the highest molecular weight

Solution:


Correct Answer is `=>` (A) maximum adsorbed
Q 2866291175

Chromatography is used to separate

(A)

plant pigment

(B)

blue and red ink

(C)

o and p-nitrophenol

(D)

All of the above

Solution:


Correct Answer is `=>` (B) blue and red ink
Q 2816191079

Choose the correct statements using the codes given below.
I. Impure glycerine is purified by vacuum distillation.
II. Glycerine dissolves in water.
III. Water is a homogeneous mixture of hydrogen and oxygen.

(A)

I and II

(B)

II and Ill

(C)

I and Ill

(D)

All of these

Solution:


Correct Answer is `=>` (A) I and II
Q 2806191078

A mixture of red and blue ink can be separated by

(A)

distillation

(B)

crystallisation

(C)

chromatography

(D)

sublimation

Solution:


Correct Answer is `=>` (C) chromatography
Q 2886191077

A mixture of methanol and acetone is separated by

(A)

fractional distillation

(B)

steam distillation

(C)

vacuum distillation

(D)

None of the above

Solution:


Correct Answer is `=>` (A) fractional distillation
Q 2876191076

Iodine is separated from sand by

(A)

sublimation

(B)

chromatography

(C)

crystallisation

(D)

evaporation

Solution:


Correct Answer is `=>` (A) sublimation
Q 2866191075

A mixture that can be separated by the sublimation method is

(A)

`MgCl_2+NaCl`

(B)

`HgCl_2+NaCl`

(C)

`AgCl+NaCl`

(D)

`BaCl_2+2NaCl`

Solution:


Correct Answer is `=>` (B) `HgCl_2+NaCl`
Q 2856191074

Steam distillation is used to separate

(A)

lemon oil

(B)

sandal wood oil

(C)

aniline

(D)

All of the above

Solution:


Correct Answer is `=>` (D) All of the above
Q 2846580473

A mixture containing `SiO_2 , NaCl` and `NH_4Cl` is taken for separating the constituents. The suitable steps required for this are

(A)

sublimation-dissolution filtration crystallisation

(B)

dissolution-filtration-crystallisation distillation

(C)

sublimation-evaporation-dissolution decomposition

(D)

dissolution-distillation-decompositionevaporation

Solution:


Correct Answer is `=>` (A) sublimation-dissolution filtration crystallisation
Q 2816580470

Which of the following are correctly matehed with the method used for separating them?
I. Lanthanides-chromatography
II. `H_2O` and `C Cl_4` -- steam distillation.
III. Glycerine and `H_2O` -- vacuum distillation
IV. Phenol and benzoic acid -- separating funnel

(A)

Only Ill

(B)

I and Ill

(C)

Only IV

(D)

IV and I

Solution:


Correct Answer is `=>` (B) I and Ill
Q 2886480377

The boiling points of two miscible liquids X and Y are close to each other. Their separation is best carried out by

(A)

simple distillation

(B)

vacuum distillation

(C)

steam distillation

(D)

None of the above

Solution:


Correct Answer is `=>` (C) steam distillation
Q 2856480374

Tinstone and wolframite is separated by

(A)

magnetic method

(B)

atmolysis

(C)

chromatography

(D)

None of the above

Solution:


Correct Answer is `=>` (A) magnetic method
Q 2846480373

A student by chance mixed acetone with alcohol. This mixture of acetone and alcohol can be separated by

(A)

filtration

(B)

separating funnel

(C)

fractional crystallisation

(D)

fractional distillation

Solution:


Correct Answer is `=>` (D) fractional distillation

States of Matter

Q 1765245165


NCERT Exemplar

Assertion : (A) The temperature at which vapour pressure of a liquid is equal to the external pressure is called boiling temperature.

Reason : (R) At high altitude atmospheric pressure is high.

(A) Both A and R individually true and R is the correct explanation of A
(B) Both A and R are individually true but R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true
Solution:

Assertion is true but reason is false.
At high altitude, atmospheric pressure is low.
Correct Answer is `=>` (C)
Q 1745245163


NCERT Exemplar

Assertion : (A) Three states of matter are the result of balance between intermolecular forces and thermal energy of the molecules

Reason : (R) Intermolecular forces tend to keep the molecules together but thermal energy of molecules tends to keep them apart.

(A) Both A and R individually true and R is the correct explanation of A
(B) Both A and R are individually true but R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true
Solution:

Both assertion and reason are true and reason is the correct explanation of assertion.
Intermolecular forces and thermal energy decide the state of matter because the
former kept the molecules together but later keep them apart.
Correct Answer is `=>` (A)
Q 1715734669

With regard to the gaseous state of matter which of the following
statements are correct ?
NCERT Exemplar
(A)

Complete order of molecules

(B)

Complete disorder of molecules

(C)

Random motion of molecules

(D)

Fixed position of molecules

Solution:

In gaseous state, molecules are in a state of random motion i.e., it is the state in which
molecules are disorderly arranged. Gaseous state have higher entropy than the liquid as
well as solid.
Correct Answer is `=>` (B)
Q 1755534464

A person living in Shimla observed that cooking food without using
pressure cooker takes more time. The reason for this observation is that at
high altitude
NCERT Exemplar
(A)

pressure increases

(B)

temperature decreases

(C)

pressure decreases

(D)

temperature increases

Solution:

Pressure at the top of a mountain [or at high altitude] is low. This suggests that boiling
takes place at lower temperature, due to which things take more time to boil.
However, in a pressure cooker, pressure is increased and hence, boiling point
increases. Thus, things comes to boil in a pressure cooker in a less period of time.
Correct Answer is `=>` (C) pressure decreases
Q 2816491370

By decreasing pressure boiling point of a liquid

(A)

increases

(B)

decreases

(C)

rnay increase or decrease depending upon temperature of liquid

(D)

remains unchanged

Solution:


Correct Answer is `=>` (B) decreases

 
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