The compound formed when aniline is gently heated with chloroform and potassium hydroxide solution is

The nanoscience of MMHNMMI RSW^BMMI

49. The compound formed when aniline is gently heated with chloroform and potassium hydroxide solution is

(a) benzonitrile (b) phenyl isocyanide (c) phenol (d) ammonia.

50. Which of the following may be prepared by Gabriel-phthalimide synthesis?

(a) aliphatic amines (b) aromatic amines (c) aliphatic amides (d) aromatic amides.

51. Schiff's bases are formed when aniline is condensed with

(a) phenols (b) aryl chlorides (c) aromatic aldehydes (d) aliphatic alcohols.

52. Nitrobenzene on reduction with Zn-dust and aqueous NH4C1 produces

(a) aniline (b) phenyl hydroxylamine (c) nitrosobenzene (d) none of these.

53. When nitrobenzene is heated with fuming HN03

and concentrated H2S04 for several hours, it gives (a) dinitrobenzene (b) trinitrobenzene (c) DDT (d) none of these.

54. At 60°C a mixture of concentrated HN03 and concentrated H2S04 converts benzene into

(a) nitrobenzene (b) /w-dinitrobenzene (c) benzene sulphonic acid

(d) 1,3,5-trinitrobenzene.

55. When nitrobenzene is reduced with Sn and concentrated HCl, the product is

(a) C6H5NH2 (b) C6H5NHC1 (c) C6H5OH (d) C6H5COOH.

56. The weight of iron which will be converted into its oxide by the action of 18 g of steam on it will be (Fe = 56, O = 16)

(a) 20 g (b) 40 g (c) 45 g (d) 42 g.

57. The weight of 50% solution of HCl required to react with 100 g of CaC03 would be

(a) 73 g (b) 100 g (c) 146 g (d) 200 g.

58. What will be the weight of oxygen that is required for the complete combustion of 2.8 g of ethylene?

(a) 2.8 kg (b) 6.4 kg (c) 96 kg (d) 9.6 kg.

59. The weight of carbon required to reduce 165 g of C02 to CO will be

(a) 40 g (b) 43 g (c) 45 g (d) 48 g.

60. The minimum amount of hydrogen required to reduce completely 7.95 g of CuO (mol. wt. 79.5) will be (a) 0.5 g (b) 1 g

61. The volume of S02 at STP formed when 1260 g of sodium sulphite react with sufficient sulphuric acid is (a) 112 litres (b) 224 litres

62. The weight of ammonium chloride required to prepare 22.4 litres of ammonia at STP is

(a) 53.5 g (b) 107 g (c) 26.75 g (d) 40 g.

63. 18 g of water is electrolysed. Volume of oxygen obtained at STP is

(a) 22.4 litres (b) 11.2 litres (c) 5.6 litres (d) 2.8 litres.

64. 15 litres of hydrogen combine with excess of nitrogen to produce ammonia. The volume of ammonia in litres formed is

(a) 5 litres (b) 8 litres (c) 10 litres (d) 12 litres.

65. 15 ml of a gaseous hydrocarbon required 45 ml of oxygen for complete combustion and 30 ml of C02 were formed. The formula of the hydrocarbon is

(a) C3H6 (b) C2H6 (C) C2H2 (d) C2H4. 66. Among the following, the most basic compound is (a) benzylamine (b) aniline

67. Toluene reacts with Cl2 in the presence of sun light to give

(a) benzyl chloride (b) benzoyl chloride (c) p-chlorotoluene (d) o-chlorotoluene.

68. Which of the following does not undergo Friedel-Craft's reaction?

(a) aniline (b) phenol (c) nitrobenzene (d) all of these.

69. Which of the following is not used as a reagent in Friedel-Craft's reaction?

(a) alcohol (b) alkene (c) chlorobenzene (d) alkyl-halide.

70. Toluene on oxidation with alkaline KMn04 gives (a) benzaldehyde (b) potassium benzoate (c) benzoic acid (d) benzo quinone.

71. The reaction of toluene with chlorine in the presence of ferric chloride gives predominantly

(a) benzoyl chloride (b) m-chloro toluene (c) benzyl chloride (d) o- and p-chlorotoluene.

72. Toluene is oxidised to benzaldehyde with chromyl chloride. The reaction is known as

(a) Oppenauer reaction (b) Etard reaction (c) Wurtz-Fittig reaction (d) Rosenmund reaction.

73. Which xylene is most readily nitrated?

(a) o-xylene (b) p-xylene

74. Which of the following shows maximum molar conductivity?

( a ) [ C O ( N H , )6] C 13 ( b ) [ C O ( N H3)5C 1 ] C 12

( c ) [ C O ( N H3)4C I2] C I ( d ) [ C O ( N H3)3C 13] ,

75. Which of the following deactivates benzene substitution?

(a) - NHR (b) - OH (c) - COOR (d) - OR.

76. 20 ml of gas was collected at STR The pressure was then doubled and the temperature gradually changed until the volume of the gas became 20 ml again. The temperature at which this happened was

(a) 173 K (b) 273 K (c) 373 K (d) 546 K.

77. A certain mass of H2 at 273°C and 3 atm pressure occupies 2 litres. What will be the volume of the gas at STP?

(a) 2/3 litres (b) 1 litre (c) 2 litres (d) 3 litres.

78. The density of a gas (mol. wt. 44.8) in gm/litre at

273 °C and 1 atm pressure is

(a) 8.9 (b) 11.2 (c) 1 (d) 2.

79. The density of a certain mass of a dry gas at 27°C and 760 mm pressure is 2.5 gm/litre. Its density at 7°C and 740 mm pressure will be (in gm/litre)

(a) 0.9 (b) 1 (c) 1.2 (d) 2.3 80. A vessel contains 1 mole of 02 at 27°C and 1 atm.

A certain amount of the gas was withdrawn and the vessel was heated to 327°C to maintain the pressure at 1 atm. The amount of gas removed was

(a) 8 g (b) 0.2 mole (c) 0.25 mole (d) 0.5 mole.

81. Which produces ammonia on reaction with caustic soda?

(a) ethyl amine (b) dimethyl amine (c) acetamide (d) aniline.

82. The isomer of an oxime is

(a) RN02 (b) R - O - C = N

83. Which of the following is most reactive towards nucleophilic substitution reaction?

(a) RC1 (b) (RC0)20

84. The most suitable reagent for laboratory preparation of acetyl chloride from acetic acid is

(a) PC15 (b) HCI (c) SOC1, (d) PC13. 85. Which ofthe following has the highest melting point?

(a) (CH3C0)20 (b) CH3CN (c) CH3CONH2 (d) CH3COCl.

86. Which of the following is not a /w-directing group?

(a) - S03H (b) - N 02 (c) - CN (d) - NH2. 87. Among the following the compound that can be most readily sulphonated is

(a) benzene (b) nitrobenzene (c) toluene (d) chlorobenzene.

88. Gammexane is (a) DDT

(b) benzenhexachloride (BHC)

89. Benzene reacts with CC14 in the presence of anhydrous A1CI3 to give

(a) tetraphenylmethane (b) chlorobenzene

10 CHEMISTRY TODAY | JANUARY '06

90. Anhydrous A1C13 in Friedel-Craft's reacton is used to

(a) generate an electrophile (b) generate a nucleophile (c) generate a free radical (d) absorb water.

91. When a solution of a primary aliphatic amine is treated with NaN02 and HCl the effervesescence occurs due to formation of

(a) CO, (b) N 02

92. The carbylamine reaction is associated with the name of

(a) Wurtz (b) Kolbe (c) Hinsberg (d) Hoffmann.

93. Hinsberg reagent is (a) benzene sulphonic acid (b) benzene sulphonyl chloride (c) /7-toluene sulphonyl chloride (d) none of these.

94. When an organic compound was treated with sodium nitrite and HCl in the ice-cold, nitrogen gas was evolved.

The compound is

(a) a nitro compound (b) a primary amine (c) a secondary amine (d) a tertiary amine.

95. An aromatic amine (A) was treated with alcoholic potash and another compound (F) when a foul-smelling gas was formed with formula C6H5NC, (7) was formed by reacting a compound (Z) with Cl, in presence of slaked lime. The compound (Z) is

(a) C6H5NH2 (b) CH3OH (c) CH3COCH3 (d) CHCI3.

96. Benzene is converted into toluene by (a) Wurtz reaction (b) Etard's reaction (c) Fittig reaction (d) Friedel-Craft's reaction.

97. In Friedel-Craft's reaction, the catalyst used is (a) Raney Ni (b) Mg and ether (c) anhydrous A1C13 (d) Na and liquid NH3. 98. Benzene undergoes predominant reactions by (a) electrophilic addition (b) nucleophilic addition (c) electrophilic substitution

(d) nucleophilic substitution.

99. In the presence of bright sunlight benzene reacts with chlorine to form

(a) chlorobenzene (b) benzyl chloride (c) hexachloro-benzene (d) benzene hexachloride.

100. The main source of aromatic compound is (a) wood (b) coal tar

A N S W E R S

1. (b) : The undesired impurities present in ores are called gangue or matrix. To remove gangue, certain substances are mixed with concentrated ore which combine with gangue to form fusible material which is not soluble in molten metal. The substances used are called fluxes and the fusible material formed during reduction process is called slag.

Si02 + CaO - » CaSiOj

flux gangue slag

2. ( a ) : Malachite - CuC03 • Cu(OH)2

Calamine - ZnC03

Galena - PbS

Dolomite - CaCO, • MgC03

3. (d) : Corrosion is defined as the gradual transformation of a metal into its combined state because of the reaction with the environment.

When iron is exposed to moist air, it is found covered with a reddish brown coating which can easily be detached. The reddish brown coating is called rust.

4. (a) : CaCO, decomposes into CaO and CO,. CaO acts as a flux as it combines with silica present as an impurity to form a fusible slag.

CaC03 CaO + CO, CaO + Si02 -> CaSi03

5. (b)

6. (b) : Molecular formula weight of the compound

= 3 0

The oxide would thus be NO = (14 + 16) = 30 At. number of N and O being 7 and 8, the total number of electrons present = (7 + 8) = 15.

7. (b) : Electronic configuration of the element may be Is2 2s2 2pb 3s1 or Is2 2s22pb 3s2.

Hence, its atomic number will be 11, 12.

8. (d) : The number of electrons in I are (6 + 3 - 1) = 8

II are (3 + 8 - 1) = 10 III are (7 + 3) = 10 IV are (6 + 3 + 1) = 10.

175

9. (d) : As we know that r„ «2/Z

For the same value of principal quantum number the radius decreases as the atomic number Z increases.

For, H, Z = 1; D+, Z = I; He+, Z = 2 ; Li2+, Z= 3 The radius of first Bohr orbit is the smallest one for Li2+. 10. (c) : Kinetic energy of the electron = — wv 1 2

and potential energy of the electron = Total energy (E) of the electron = K.E.

—mv 1 2 2

Ze1 4 7 t £0r + P.E.

Ze1

4 ne0r Centripetal force = (coulombic atractive force

between electron and proton) mv

E = Ze2

47te0/-' mv2 = Ze

8 i t E0r

Ze Zez

47tE 0r

Ze2

8ne0r [8ne0r

That is E <*= Mr.

11. ( b ) : 4Ag + 8NaCN + 2H20 + O,

4NaAg(CN)2 + 4NaOH

sodium argentocyanide

NaAg(CN)2 + Zn -> Na2Ag(CN)2 + 4NaOH

soluble complex

12. ( a ) : Invar is an iron alloy containing 36% Ni.

13. (b)

14. (c) : Laminaria species contain 0.5% of iodine in their ashes (known as kelp) in the form of iodides.

15. (c) : Glass being a mixture of sodium and calcium silicates reacts with hydrofluoric acid forming sodium and calcium fluorosilicates respectively.

Na2Si03 + 3H2F2 Na2SiF6 + 3H20 CaSi03 + 3H2F2 -> CaSiF6 + 3H20 16. (c) Species Z e Z/e

Mg2+ 12 10 12/10 = 1.2 Na+ 11 10 11/10 = 1.1

F- 9 10 9/10 = 0.9

Al3+ 13 10 13/10 = 1.3 We know the bigger the value Z/e, the smaller is the ionic radius.

Hence increasing order of radius AI3+ < Mg2+ < Na+ < F".

17. (c) : All these species are isoelectronic.

Again the larger value of proton/electron the smaller is

the radius. The oxide ion has only 8 protons, the ratio is the smallest one. Hence 02~ has largest radius.

18. ( b ) : In cf-block elements the electrons occupy the c/-subshell and the last two principal shells are incomplete.

Again, after filling the ns orbital the electron enters the {n-\)d orbital.

19. (b) : We know that, velocity = - T

no. of Bohr orbit Therefore, the velocity of the electron in the third Bohr orbit = x/3.

, he 20. (c) : As we know, £ = «o = —

1 £, _ X2 _ 4000 _ 2 E x — . Therefore, c - , ~ ,

X ' E2 2000 1

21. (d) : As others (1), (2) and (3) reacts with Cl2. 22. (b)

23. (d) : The structure of S2072" is

/ s — o — s ^ . .

•• :o: :o:

Therefore, it has no S - S bond. Rest of them have S - S bond in their structures.

24. (b) : H,C204

cone. H , S O . . . 2 4 COT + CO,T

dehydration of H20

25. ( a ) : S02 + 2H2S 2H20 + 3S

Here oxidation number of S reduces from +4 to 0.

But it oxidises H2S (-2 to 0)

So, S02 in this reaction acts as oxidising agent.

26. (a) : All these elements belong to period 3 in the periodic table. The first ionization energy increases in a period, with the exception that ionisation energy of group IIIA is less than that of group IIA element.

Hence, the order of increasing ionisation energy is Na < Mg > Al < Ai.

27. (c) : As we know that the noble gases have the highest value of first ionisation energy in their period, hence noble gases occupy the highest points in the curve.

28. (d) : Isoelectronic cations have smaller radius than anions and the radius increases in a group.

29. (d) : Electronic configuration of A (Z = 13), 2, 8, 3

Electronic configuration of B (Z = 8), 2, 6

50 CHEMISTRY TODAY | JANUARY '06

A by losing 3 electrons and B by gaining two electrons achieve the noble gas configuration.

Hence, valency of A is +3 and that of B is -2. Therefore, the formula of the compound is A2B3.

30. (d) : The cation in all the compounds is the same Ca2+. The anion is halide ion,

The size of the iodide ion is greatest of all other halide ions. By Fajan's rule, the maximum covalent character of these exists in Cal2.

31. (d)

32. (d) : 2 H N 03 ~H 2° > N205

33. (c): For the manufacture ofHN03, reactions taking place in air are as follows:

N2 + 02 ^ 2NO - 43,200 calories 2NO + 02 -> 2NO,

2N02 + H20 HNO3 + HN02

3HN02 HN03 + 2NO + H20

34. ( d ) : As the molecular formula of phosphorus is P4. 35. (b): As in orthophosphoric acid (H3P04), number of ionisable hydrogen atoms (basicity) is three.

36. (c) : The Lewis structures of these compounds are

: C l :

.. I

: C I C

-•• I :ci: oo

H I

H - N - H

ci: ,[ca2+] [:ci:]_

(b)

M A

L J • H H

M W) (a) and (d) have only covalent bonds

(b) contains an ionic bond

37. (a) : Considering the size of the F, N, O the atom of the smallest radius of the three is fluorine and fluorine is the most electronegative atom. The H-bond in HF is, therefore, shortest in length.

38. (b): The species exhibiting resonance requires the presence of a rc-bond or the lone pair suitably placed in the structure of molecule or ion.

The structures are

CH3: CH2: O : H

: N = N ^ O 0 = S—O

-10 C H E M I S T R Y T O D A Y | FEBRUARY '06

UjpJ » C H3- C H , - 0 - H ,

® ..'— .. © : N = N = 0 : , : 0 = S — O:

The condition is not present in ethanol (C2H5OH).

39. (c) : This atomic weight of calcium = 40 .". 40 g of Ca make 1 mole

10 g of Ca make — x 10 = 0.25 mole.

40. (a) : Since, one mole of oxygen = 32 g

= 6.02 x io23 molecules of 02

= 22400 ml 02 at STP

Number of molecules of oxygen in 280 ml of 02 at STP = x 6.02 x 10280 ²³ molecules

22400

= 7.53 x io21 molecules.

41. (c) : v 6.02 x io23 molecules of C02

= 1 mole of C02

1021 molecules of CO, = 10 ^,21 10 ,-2 6.02 xlO23 6.02 mole 200 1

Now, 200 mg of C02 = — : * — mole 10 _9

= — x l O mole 22

Number of mole of CO, left = 10 1 xlO"

42. (a) : Millimoles of NaOH Mg of NaOH

22 6.02,

= 3 x 10"3 mole.

1600 formula wt. of NaOH in mg 40x 1000 _ *600 _ 0 mj | j j m o l e

40,000 43. (b): As,

vol. of methane at STP _ No. of molecules of CH4

vol. of oxygen at STP No. of molecules of O, 3x10 ²²

1.12

0.56 no. of molecules of 02

3xl()22 x0.56

=> No. of molecules of O, =

44. (c) : As,

1.12 1.5 x io22. No. of molecules of 02

No. of molecules of N2

_ moles of 02 ^ Avogadro's number moles of N2 Avogadro's number 13

wt. of O,

mol. wt. of O, 1/32 1 28 7 wt. of N , 4/28 32 4 32 mol. wt. o f N2

45. (c) : Since, 24 g of magnesium contains 6.02 x 10" atoms This reaction is called isocyanide reaction and is used as a qualitative test for primary amines.

50. (a)

51. (c): Aniline reacts with benzaldehyde in 1 : 1 molar ratio to produce benzalaniline.

(also called Schiff's base or anil) C6H5NH2 + O = CH - C6H5 A

2.8 kg of ethylene are completely burnt by

^ = 9.6 kg.

Again, 2 g of hydrogen is equivalent to 22400 ml of H, at STP.

given volume wt. of unknown lit.

6 4 CHEMISTRY TODA\ JANUARY '06

given volume _ unknown volume no. of molecules no. of molecules 15 x

j 2

65. (d) : Combustion reaction of hydrocarbon CrHv

, y i

A- = 10 litres.

C , HV+ [ X + ^ I O2= * C O2+ | H2O

v o'' x v 0'

1 vol

15 ml 15| -T + - J ml I5x ml

Now 15A: = 30 (given)

(As volume of C02 is 30 ml) . x = 2.

Again, 15lx + ^-J = 45 (volume of 02 reacted)

^- = 3 - j c = 3 - 2 = 1

=> jc + —= 3

4 4

=f y = 4.

;. Formula of hydrocarbon = CVH;. = C2H4. 66. (a)

benzyl chloride

68. (d) : The reaction of an alkyl halide or acyl halide with benzene in the presence of a Lewis acid, generally A1C13, is known as Friedel Craft's reaction.

69. (c)

70. (b) : - CH3 group is oxidised to - COOH group.

C H3 C H3 C H3

71. ( d ) : [ O j

72. (b) :

Cl,

FeCl3

C H ,

o-chlorotoluene CI p-chlorotoluene

CHO

C S2 (25-45°C)

(toluene) (benzaldehyde)

So, toluene is conveniently oxidised with Etard reagent (chromyl chloride CrO,Cl2)to benzaldehyde. This reaction is known as Etard reaction.

73. (c)

74. (a): Because it contains maximum number of ions.

75. (c)

76. (d) : Here K, = 20 ml, K, = 20 ml r, = 273 K, T2 = ? Pt = 1 atm, P2 = 2 atm

20x20x273 i2

-W _P2V2

75 T-> P\V\ 1x20 = 546 K.

77. (d) : Pf = 3 atm, P2 = 1 atm, V2 = 2 litres, V2 = ?

= (273 + 273) K = 546 K, T2 = 273 K

. ,

^IWi

As we know from the gas equation. 5H r. P~>

lr P.V.T, 3x2x273 V-, = 1 1 2 = = 3 litres.

TXP2 546x1

PM RT

= 1 gm/litre.

78. (c) : As we know that, density, P = Here, we are given P = 1 atm,

R = 0.082 litre atm K"1 moL1

M = 44.8 gm/mole, T=(273 + 273) K = 546 K 1 44.8

.'. P = x

0.082 546

79. (d) : As we know, = P{l] P2T2

Here we are given p, = 2.5 g/litre, p, = ? 7, = (273 + 27) K = 300 K

T2 = (273 + 7) K = 280 K Px = 760 mm, P2 = 740 mm

p,r, P2 _ 2.5x280x740

P2 = „ = 2.3 g/litre.

P\ 7] 760x300

80. (d) : Suppose the gas removed = x mole

The amount remaining in the vessel = (1 - x ) mole Volume is constant and pressure is kept the same under this condition.

nlTl = n2T2

Here, nx = 1 mole, n2 = (1 — x) mol r, = 300 K, T2 = 600 K

Therefore, 1 x 300 = (1 - x) 600 1 = 2(1 - x ) = 2 - 2x .'. x = 1/2 mole = 0.5 mole.

81. (c) : CH3CONH2 + NaOH (aq)

CHjCOONa + NH3

This is also test for amide - (CONH,) group.

82. (d)

83. (c): Reactivity towards nucleophilic substitution lies in the following sequence.

RCOCI > (RC0)20 > RCOOR' > RCONH, Nucleophilic substitution takes place readily at an acyl carbon than at saturated carbon. Thus for nucleophilic substitution acid chlorides are more reactive than alkyl chlorides; amides are more reactive than amines and esters 13

are more reactive than ethers.

RCOCI > RC1, RCONH2 > RNH2, RCOOR' > ROR' 84. (c) : Thionyl chloride is the better reagent because the byproducts of the reaction are the gases S02 and HCI, which are easily separated.

85. (c)

86. (d) : - NH2 is an o-, p-directing group, as it has at least one pair of non-bonding electrons on the atom adjacent to the benzene ring.

87. (c)

88. (b) : Asgammexane is nothing but C6H6C16 (B.H.C).

A1C1, 89. (d) : C6H6 (excess) + CCI4

(C6H5)3C - CI (C6H5)3C - CI is called triphenyl methyl chloride.

90. (a) : Reaction —> alkylation

Reagent —> R - CI Catalyst AICI-, Electrophile —> R

Product CfiH, - R (CH3 )

91. (c) : C2H5NH2 or R - N H2

(NaNQ2+HCl)

or HN02 (0°C) » C , H⁵O H + N , 92. (d)

93. (b) : Benzene sulphonyl chloride (C6H5S02C1) is known as Hinsberg's reagent, and used for the separation of primary, secondary and tertiary amines.

94. (b): This reaction is used to make distinction between primary, secondary and tertiary amines.

95. (c) : C6H5NH2 + CHC13 + 3KOH (afc) ->

A Y

C6H5NC + 3KC1 + 3H20 CH3COCH3 + 3C12 CCl3COCH3 + 3HC1

OH CCljCOCHj 2CHCI CHjCOO-^

C a < +

^ O H C C 13C 0 C H3 C H , C O O '

; c a

96. (d) - C H j C l A1C1, ^{C H}³

(benzene) (toluene)

This reaction is called Friedel-Craft's reaction.

98. (c) bright sunlight (U.V.),

> C6H6C16

97. (c)

99. (d) : C6H6 + 3C12

(B.H.C) 100. (d) : Coal and petroleum are the two important sources of aromatic hydrocarbons.

In document Chemistry Question Bank for Hiighschool (Page 173-180)