chemistry · xenon hexafluoride reacts with silica to form a xenon compound the oxidation state of...

35
Chemistry Single correct answer type: 1. Which one of the following species is paramagnetic in nature? (A) (B) (C) (D) Solution: (D) The number of unpaired electrons and electronic configuration of the given species is shown below () [ ] [] No. of unpaired electron () [ ] [] No. of unpaired electron () [ ] [] No. of unpaired electron () [ ] [] Number of unpaired electrons The correct option among the following is () 2. Given that, for the reaction, () ( ) ( ) The bond dissociation energy of is (A) (B) (C)

Upload: others

Post on 03-Feb-2020

16 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Chemistry

Single correct answer type:

1. Which one of the following species is paramagnetic in nature?

(A)

(B)

(C)

(D)

Solution: (D)

The number of unpaired electrons and electronic configuration of the given species is

shown below

( ) [ ] [ ]

No. of unpaired electron

( ) [ ] [ ]

No. of unpaired electron

( ) [ ] [ ]

No. of unpaired electron

( ) [ ] [ ]

Number of unpaired electrons

The correct option among the following is ( )

2. Given that, for the reaction,

( ) ⁄

( ) ⁄

( ) ⁄

The bond dissociation energy of is

(A) ⁄

(B) ⁄

(C) ⁄

Page 2: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

(D) ⁄

Solution: (C)

Given,

In this reaction, one mole of is formed

of the reaction will remain same,

i.e., ⁄

Let the bond dissociation energy of bond be

For the given reaction,

( ) ( )

( )

( )

3. The pair of structures given below represents

(A) Chain isomers

(B) Position isomers

(C) Tautomers

(D) Metamers

Solution: (B)

The pair of the given

represents position isomers. In case of position isomers, the difference lies in the

position of substituent groups or atom in the same chain.

Page 3: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

4. In the extraction of copper from its sulphide ore, the metal is formed by the reduction

of with

(A)

(B)

(C)

(D)

Solution: (C)

In the extraction of copper from its sulphide ore, the metal is formed by the reduction of

with This reaction completes with the process of auto-reduction. Chemical

reaction occurring in this reaction is as follows

The molten copper is allowed to cool. During cooling, dissolved comes out in the

form of blisters, so it is called blister copper.

5. For the following reaction,

( ) ( ) ( ) ( ) at

Then, for this equilibrium is

(A)

(B)

(C)

(D)

Solution: (B)

Given,

For equilibrium, the Gibb’s free energy is calculated by using the formula.

or,

Page 4: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

6. Xenon hexafluoride reacts with silica to form a xenon compound The oxidation

state of xenon in is

(A)

(B)

(C)

(D)

Solution: (C)

Xenon hexa fluoride reacts with silica to form as

The oxidation state of xenon in is as calculated below:

Let the oxidation state of is

( ) ( )

7. Neopentyl chloride reacts with benzene in presence of a Lewis acid ( ) to form

(A)

(B)

(C)

(D)

Solution: (B)

Page 5: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

8. Lead is extracted from galena ( ) either by following ways.

( ) →

( ) →

Auto-reduction process is

(A) →

(B) →

(C) Both →

and →

(D) None of these

Solution: (B)

In auto-reduction, no external reducing agent is required. In such reduction reaction, the

product formed acts as a reducing agent and reduces the oxide to metal. Thus, only

reaction is called auto-reduction.

( ct as a reducing agent)

9. In the reaction,

Page 6: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

The major product formed is

(A)

(B)

(C)

(D)

Solution: (C)

The given reaction is an example of Perkin condensation. In this, reaction aromatic

aldehydes react with acid anhydride of an aliphatic acid in presence of sodium salt of

same acid to form unsaturated acid. The steps involved in the process are as

follows

Thus, the correct option is (C).

10. Which one of the following represents the correct structure of cellulose?

(A) Branched, ( ) and ( ) glucose

(B) Unbranched, ( ) glucose

(C) Branched, ( ) glucose

(D) Unbranched, ( ) glucose

Solution: (D)

Cellulose has a straight chain polysaccharide composed only of The

glucose glucose. These glucose units are linked together by

glycosidic linkage. The structure is shown below:

Page 7: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Structure of cellulose

11. The correct formula for plaster of Paris is

(A)

(B)

(C)

(D)

Solution: (C)

Plaster of Paris (POP) is a hemihydrate of calcium sulphate. Its chemical formula is

[ ( ) ]

12. The value of for the reaction,

is At a given time, the composition of reaction mixture is

[ ] [ ] [ ] In which direction, the reaction will proceed?

(A) Forward direction

(B) Reverse direction

(C) No net reaction occur

(D) None of these

Solution: (B)

For the reaction, the reaction quotient is given by

[ ][ ] [ ] ⁄

Given that,

[ ] [ ] [ ]

Page 8: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Then, ( )( )

( )

As, so the reaction will proceed in the reverse direction.

13. Which of the following chemicals are used to manufacture methyl isocyanate that

caused "Bhopal tragedy"?

( ) Methylamine

( ) Phosgene

( ) Phosphine

( ) Dimethylamine

(A) ( ) and ( )

(B) ( ) and ( )

(C) ( ) and ( )

(D) ( ) and ( )

Solution: (A)

Methyl isocyanate ( ) is industrially prepared by the reaction of methyl amine

and phosgene (carbonyl chloride).

14. The correct order of ease of adsorption of the hydrated alkali metal ions on an ion

exchange resin is

(A)

(B)

(C)

(D)

Solution: (A)

Ease of adsorption of the hydrated alkali metal ions on an ion exchange resin

decreases as the size of the alkali metal ion increases. Since. the order of the size of

the alkali metal ions is

Page 9: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Thus, the ease of adsorption follows the order

15. Identify the major product that is obtained on treatment of ( ) with

⁄ is

(A) ( )

(B)

(C)

(D)

Solution: (B)

ccording to Saytzeff’s rule, dehydrohalogenation occur in such a way that the major

product is more highly substituted product.

( )

( ajor)

( inor)

16. Among the following, the non-aromatic heterocyclic compound is

(A) Piperidine

(B) Pyrrole

(C) Furan

(D) Pyridine

Solution: (A)

Pyridine is aromatic, since, it satisfies all the conditions of a compound to be aromatic

(here, lone pair on atom is and used in delocalization).

Pyrrole is also aromatic and here, lone pair on atom is used in delocalization.

Page 10: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Furan also follows Huckels rule and other conditions for a compound to be aromatic.

Piperidine is non-aromatic because, in it rule is not followed and moreover, no

delocalization of electron takes place.

17. If ion is larger than ions and ion is larger than ion, which of the

following will be stable salt in water?

(A) Sodium chloride

(B) Sodium sulphide

(C) Magnesium sulphide

(D) Magnesium chloride

Solution: (C)

Higher the lattice energy, lower the solubility and more stable the salt in water. Since,

lattice energy varies directly with charge. Therefore, among the four combinations

given, the lattice energy of is higher than those of and . Hence,

is stable salt in water and least soluble salt.

18.

Product P is

(A)

Page 11: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

(B)

(C)

(D)

Solution: (B)

19. Which of the following is correct statement?

(A) Aluminum dissolves in dilute mineral acids but is made passive by concentrated

nitric acid.

(B) Aluminum vessel can be used as storage of

(C) Aluminum chloride does not dissociate in water.

(D) is soluble in anhydrous .

Solution: (A)

( ) Aluminum is made passive by due to formation of oxide layer. Hence,

does not react further but other acids react.

( )

( ) reacts with as

Page 12: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Thus, cannot be stored in a vessel made of

( ) Aluminum chloride dissociate in water.

( ) is insoluble in anhydrous

Thus, the only correct statement among the given options is ( ).

20. If molar conductivity of and ions are and respectively,

then the molar conductivity of at infinite dilution is

(A)

(B)

(C)

(D)

Solution: (D)

Given,

As we know that,

21. An atom forms face centred cubic crystal with density ⁄ and edge

length The molecular mass of atom is is

(A)

(B)

(C)

(D)

Solution: (B)

Given,

Density ( ) ⁄

Edge length ( )

Page 13: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

( )

The molecular mass of atom in a lattice can be calculated by using the formula

( ) ( )

22. In a crystalline solid, having formula , oxide ions are arranged in cubic close

packed lattice while, cations are present is tetrahedral voids and cations are present

in octahedral voids. The percentage of tetrahedral voids occupied by is

(A)

(B)

(C)

(D)

Solution: (A)

In a cubic close packed lattice of oxide ions, there would be two tetrahedral and one

octahedral void per oxide ion.

Since, the formula shows the presence of oxide ions, the number of tetrahedral voids

is eight and that of octahedral voids is four. Out of the eight tetrahedral voids, one is

occupied by .

Percentage of tetrahedral voids occupied

23. Conversion of oxygen into ozone is non-spontaneous at

(A) Low temperature

(B) All temperature

(C) High temperature

(D) Room temperature

Page 14: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Solution: (C)

Ozone is not stable at high temperature.

So, it decomposes into oxygen at high temperature.

Thus, the reverse of this reaction is non-spontaneous at high temperature.

24. A flask contained at , and a flask contained at

. The two flask were then connected so that each gas filled their combined

volume. Assume, no change in temperature, total pressure is

(A)

(B)

(C)

(D)

Solution: (D)

Given,

Total number of moles

Total volume

Total pressure ( )

Page 15: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

25. For the dot structure shown, the most likely elements and are

(A) Carbon, fluorine

(B) Carbon, hydrogen

(C) Carbon, oxygen

(D) Oxygen, carbon

Solution: (A)

is tetravalent without lone pair. has three lone pair and one bond pair. Thus, is

carbon and is halogen or, carbon, fluorine

26. Valence electrons in the element are and that in element is . Most probable

compound formed from and is

(A)

(B)

(C)

(D)

Solution: (D)

Valence electrons in

Valence electrons in

Thus, is electropositive and is electronegative, can lose three electrons and can

gain two electrons to attain stable configuration. Hence, exists as and as

and compound is

Page 16: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

27. A compound, containing only carbon, hydrogen and oxygen has a molecular weight

of . On complete oxidation, it is converted into a compound of molecular weight is .

The original compound is

(A) Alcohol

(B) Acid

(C) Aldehyde

(D) Ether

Solution: (C)

On complete oxidation, the obtained compound shows increment in molecular weight of

only 16. It means only one oxygen atom is added here. This condition is fulfilled by only

aldehyde which on oxidation gives acid.

[ ]→

Hence, original compound must be an aldehyde. The aldehyde with molecular weight

is acetaldehyde.

olecular

weight 44

[ ] →

olecularweight 6

28. Number of photons emitted by a ( ) yellow lamp in is ( of yellow

light is )

(A)

(B)

(C)

(D)

Solution: (C)

As we know that,

…(i)

( )

Putting the value in Equation (i) we get

Page 17: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

29. In Kjeldahl's method, the nitrogen present in an organic compound is quantitatively

converted into

(A) Gaseous ammonia

(B) Ammonium sulphate

(C) Ammonium phosphate

(D) Ammonia

Solution: (D)

In Kjeldahl’s method, the nitrogen is quantitatively converted into ammonia by heating

with

From organic

ompound

→ ( )

( )

30. In the reversible reaction,

the rate of disappearance of is equal to

(A)

[ ]

(B) [ ] [ ]

(C) [ ] [ ]

(D) ( )[ ]

Solution: (B)

Rate of reaction

[ ]

[ ] [ ]

Rate of disappearance of

i.e. [ ]

[ ]

[ ]

Page 18: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

31. If ( ) and ( ) then the of the cell

| ( )|| ( )| is

(A) Equal to

(B) Less than

(C) Greater than

(D) Equal to

Solution: (C)

The cell reaction is

From Nernst equation

( )

32. For the electrochemical cell, | || || | the overall cell reaction is

(A) ( )

(B)

(C) ( )

(D) ( )

Solution: (C)

For the electrochemical cell,

| || || |

The cell reaction is

Page 19: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

33. Which one of the following electrolytes has the same value of van’t Hoff factor ( ) as

that of [ ( ) ]

(A) ( )

(B)

(C) [ ( ) ]

(D) ( )

Solution: (A)

The value of van’t Hoff factor of the given molecule is as follows:

( )

[ ( ) ] [ ( ) ]

( )

The van’t Hoff factor for [ ( ) ] is

[ ( ) ] [ ( ) ]

( ) has the same value of van’t Hoff factor as that of [ ( ) ]

34. The van’t Hoff factor for ( ) solution is The degree of dissociation

is

(A)

(B)

(C)

(D)

Solution: (B)

Total number of moles

Then, van’t Hoff factor,

or,

Page 20: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

or,

% dissociation

35. The IUPAC name of the following compound is

(A) propylpent ene

(B) ethylpent ene

(C) ethylhex ene

(D) ethylhex ene

Solution: (D)

Select the longest possible carbon atom chain, number the chain and write the name of

compound according to IUPAC rules. Thus, the correct IUPAC name of the compound

given is

36. Bleeding due to a cut can be stopped by applying ferric chloride solution in the

laboratory. This is due to

(A) Coagulation of negatively charged blood particles by ions.

(B) Coagulation of positively charged blood particles by ions.

(C) Reaction taking place between ferric ions and the hemoglobin forming a complex.

(D) Common element, iron, in both and hemoglobin.

Solution: (A)

Bleeding due to a cut can be stopped by applying or alum solution. This is due to

coagulation of negatively charged colloidal blood particles (albuminoid substance) by

positively charged ions. These substances are used as styptic (which check the

flow of blood).

37. Relative stabilities of the following carbocations will be in the order

Page 21: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

(A)

(B)

(C)

(D)

Solution: (A)

The dispersal of the charge stabilises the carbocation. More the number of alkyl groups;

the greater is the dispersal of positive charge and therefore more is the stability of

carbocation. Thus, the correct order is

38. Among the following species, the one which become paramagnetic on heating at

is

(A)

(B)

(C)

(D) Both and

Solution: (D)

All magnetically ordered solids, i.e. ferromagnetic; antiferromagnetic; ferrimagnetic

changes to paramagnetic state at high temperature because of the randomisation of

spins.

Ferrimagnetic species, such as (magnetite) and ferrites, i.e. and

loses ferrimagnetism on heating and transforms to paramagnetism.

39. Which of the following is not a surfactant?

(A) ( ) ( )

(B) ( )

(C) ( )

(D) ( )

Page 22: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Solution: (B)

Every surfactant contains two parts a hydrophobic part and a hydrophilic part. The

compound ( ) contains only hydrophobic part but no hydrophilic part,

hence, it is not a surfactant.

All other options are surfactant

( ) ( )

( )

( )

40. In the complex [ ( ) ] the oxidation number of is

(A)

(B)

(C)

(D)

Solution: (B)

Let the oxidation number of is in the complex [ ( ) ]

( ) ( )

Thus, the oxidation number of is

41. Arrange the following polymers in increasing order of their intermolecular forces.

Nylon buna polythene, neoprene

(A) Neoprene buna nylon polythene

(B) Neoprene buna polythene nylon

(C) Polythene nylon buna neoprene

(D) Polythene buna nylon neoprene

Solution: (B)

The increasing order of intermolecular forces in different polymers is elastomers

plastics fibres. So, in order to solve such problem, first classify the given polymer into

Page 23: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

the above classes and then arrange them in increasing order of forces. Neoprene

(synthetic rubber) is an elastomer, buna is also an elastomer, polythene is plastic

and nylon is a fibre. So, the increasing order of intermolecular forces of the given

polymer is

Neoprene buna polythene nylon

42. The product of electrolysis of aqueous solution on anode and cathode

respectively is

(A) and

(B) and

(C) and

(D) and

Solution: (A)

In case of electrolysis of aqueous oxidation and reduction reaction occurs at

anode and cathode respectively as shown below:

<b>At cathode</b>

( )

( )

( )

<b>At anode</b>

( )

( )

Net cell reaction is as follows

( ) ( ) ( ) ( )

( )

( )

Thus, the product of electrolysis of solution on cathode and anode is and

43. In adiabatic conditions, mole of gas at is expanded such that its volume

becomes times. Then, the work done is ( )

(A)

(B)

(C)

Page 24: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

(D)

Solution: (D)

Given,

In adiabatic conditions

( )

or,

(

)

(

)

(

)

Or,

Thus, hence, cooling takes place due to expansion under adiabatic condition.

( for adiabatic change)

because gas expands.

Then, ( )

( )

44. The compounds and are distinguished by

(A) and in

(B) in

(C) Dilute

(D) and naphthol

Solution: (D)

Page 25: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

45. Alkali metals readily dissolve in liquid ammonia to give blue coloured solutions. The

blue colour is believed to be due to

(A) Ammoniated cations

(B) Ammoniated anions

(C) Ammoniated electrons

(D) Ammoniated cations and ammoniated electrons

Solution: (C)

Alkali metals readily dissolve in liquid ammonia. It gives blue coloured solution due to

ammoniated electrons.

The reaction is shown below:

( ) ( ) ( )

( ) lue colour

46. ⁄→

( )

( ) ⁄→

What is the product is the above reaction?

Page 26: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

(A) Methyl ethanoate

(B) Ethanoic acid

(C) Propanal

(D) Methyl propanoate

Solution: (A)

The reaction is as follows

Hence, the product is methyl ethanoate.

47. If osmotic pressure of ( ⁄ ) solution of sucrose is same as ( ⁄ ) solution

of then the molecular mass of ( ⁄ ) is

(A)

(B)

(C)

(D) None of these

Solution: (A)

solution of sucrose ( ⁄ ) means of sucrose is dissolved in of solution.

Similarly, ( ⁄ ) solution of means of present in of solution.

As we know that, osmotic pressure ( ) or

where number of moles

of solute.

Since, (for sucrose solution)

(for solution)

Page 27: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

[

]

Molecular weight

Molecular weight

48. Which of the following is disproportionation reaction?

(A)

(B)

(C)

(D)

Solution: (D)

Reactions in which the same substance is oxidized as well as reduced are called

disproportionation reaction. Writing the oxidation number of each element above its

symbol in the given reactions.

Thus, in the reaction of and is both oxidized as well as reduced. Hence, the

oxidation number increases from in to in and decreases from in

to in

49. Among the following, the suitable reagent for Wurtz reaction is

(A) ⁄

(B) ⁄

(C) ⁄

(D) ⁄

Solution: (B)

Page 28: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

The suitable reagent for Wurtz reaction is ⁄ An ethereal solution of an alkyl

halide is treated with sodium to produce higher alkanes. This reaction involves the

function of new

bond. e.g.

thyl bromide

ropane

50. Which type of drugs come under anti-microbial drugs?

(A) Antiseptics, antacids, antihista mines

(B) Tranquilizers, antiseptics, antifertility

(C) Tranquilizers, analgesics, antiseptics

(D) Antiseptics, antibiotics, disinfectants

Solution: (D)

Bacteria, virus, fungi and other pathogens are microorganisms. These may cause

diseases in human beings and animals. An antimicrobial drug prevents the development

or inhibit the pathogenic action of microorganisms such as bacteria (antibacterial drug),

virus (antiviral drugs), fungi (antifungal drugs) or other parasite (antiparasite drugs

selectively). Antibiotics, antiseptics and disinfectants are antimicrobial drugs.

51. Which of the following pair behaves as strong and weak base hydride respectively

(A)

(B)

(C)

(D)

Solution: (B)

The basic strength of given hydrides decreases in the order as follows

Page 29: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

This is due to the decrease in the availability of the lone pair of electrons which depends

on the size of central atom that increase from to . Therefore, and acts as

a strong and weak base hydride respectively.

52. mong the following, the correct formula of arshall’s acid is

(A)

(B)

(C)

(D)

Solution: (B)

The correct formula of arshall’s acid is It is known as peroxodisulphuric acid

having Sulphur (S) in oxidation state. The structure of this acid is shown below:

53. When hydrogen peroxide is added to acidified solution of dichromate a deep

blue coloured complex of chromic peroxide is formed. Oxidation state of in

is

(A)

(B)

(C)

(D)

Solution: (C)

When is added to an acidified solution of dichromate a deep blue complex

chromic peroxide, is formed.

( )

This deep blue coloured complex has the following structure

Page 30: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Let the oxidation state of be

In ( )

( ) ( )

54. When phenol is treated with and followed by acidification,

salicylaldehyde is obtained. Which of the following species is involved in the above

mentioned reaction as intermediates?

(A)

(B)

(C)

(D)

Solution: (A)

On refluxing alkaline solution of phenol with at and on subsequent

acidification, hydroxy benzaldehyde (salicylaldehyde) is obtained. This reaction is

known as Riemer Tiemann reaction.

<b>Mechanism</b>

Page 31: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

correct option is ( )

55. Which of the following is the correct sequence of step involved in the mechanism of

Cannizzaro reaction?

(A) Nucleophilic attack, transfer of and transfer of

(B) Transfer of transfer of and nucleophilic attack

(C) Transfer of nucleophilic attack and transfer of

(D) Electrophilic attack by transfer of and transfer of

Solution: (A)

Cannizzaro reaction involves the aldehydes which do not have an hydrogen atom,

undergo self oxidation and reduction reaction on heating with conc. alkali.

<b>Mechanism</b>

<b>Step I:</b> Attack of nucleophile to the carbonyl carbon.

<b>Step II:</b> Transfer of hydride ion from anion I to second molecule of aldehyde

and finally rapid transfer of proton takes place.

Page 32: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

56.

What is the product is the above reaction?

(A)

(B)

(C)

(D)

Solution: (D)

In the first step, hydroxyl group of carboxylic acid is replaced by chlorine atom on

treating with which on further reaction with produced an amide. The amide

undergoes Hoff mann bromamide reaction to produce an amine.

Page 33: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

57. Red blood cells are placed in a solution and neither haemolysis nor crenation

occurs. Therefore, the solution is

(A) Hypertonic

(B) Hypotonic

(C) Isotonic

(D) Isotopic

Solution: (C)

When red blood cells are placed in a solution and neither hemolysis nor crenation

occurs. This means that solution is isotonic in nature, since in isotonic solution, there is

no process of osmosis takes place.

58. If is element of actinoids series, the degree of complex formation decreases in

the order

(A)

(B)

(C)

(D)

Solution: (B)

The higher the charge on the metal ion, smaller is the ionic size and more is the

complex forming ability. Thus, the degree of complex formation decreases in the order

Page 34: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

The higher tendency of complex formation of as compared to is due to high

concentration of charge on metal atom

59. A chemical reaction was carried out at and The rate constant were

found to be and respectively, then

(A)

(B)

(C)

(D)

Solution: (B)

For every rise, rate constant gets doubled. Hence, for every rise, rate

constant will be times.

Therefore, according to the given statement,

60. Which of the following compound can exhibit tautomerism?

(A)

(B)

(C)

(D)

Solution: (B)

Presence of atom along with a multibonded functional group is an essential

condition for exhibiting tautomerism.

Page 35: Chemistry · Xenon hexafluoride reacts with silica to form a xenon compound The oxidation state of xenon in is (A) (B) ... The structure is shown below: Structure of cellulose 11

Satisfies this condition, therefore exhibit tautomerism.