Type of Question with Method & Solution for H. S. and Other Competitive Entrance

Examination(Medical / Engineering)

Class - Xl

Ghemical bonding

1: The maximum number of hydrogen bonds hata weter molecule can form is(a)4 (b) 3(c)2 (d) 5

2: Bond-order of Be, and q resp€ctively are(a) 0, 2 (b)2,2(c) 2, 0 (d) 1, 1

3: AlCl3.sH,O is(a) an ionic compound(b) a covalent compound(c) a clordinate covalent cornpound(d) ceordinate compound

4: The neu,ly discovered allotrope of carbon thathaving a football like structure is(a) C.o; Fullezene (b) C6o:Fluorine

' (c) C6. ; Fullerene (d) Clro ;Allene5: The normalstructure of lCtJis

(a) trigonal (b) oc{ahedral(c) square planar (d) tdgonal bipyramidal

6: Molecular orbital theory was proposed by(a)Pauling€later (b)Mulliken-Hund(c) Gilepsy-Pauling (O Sidgwick-Sugden

7: Vvhich of lhe follo/ving moleqieMons haslavea linearstructure?

(a) SnCl, (b) Ncc-(c)H,O (d) cS,

E: The electronegativity of H and Clare 2.1 and3.0 respedively. The coned statement(s) aboutthg nature of HCIis/are(a) HCI is'17% ionicand E3o6 covalent(b) l7% covalent and 83% ionic(c) 50% covalent and 50% ionic(O purely ionic and having no mvalent charader

9: The bondorder of C - O bond and charge at O.

atoms for COr:- (carbonate ion) are

e3e(a) 1.25, a (b11.25, Z

2ee(c) 1.33, 5 (d) 1.33, 5

'10: ln a homonuclear molecule, which of thefollo,ying sets of orbitals is degenerated?

(a) oz. and oi (b) ttzo,atd nzp,

(cl n2,-andfi2?- (d) oro-ndrir,

11: The number of o and * bonds in dicyanogen(CN), are

(a) 2o+3r (b) 3o+2r(c)3o+4n (d) 4c+3lr

12: Which of the follor/ing carbon (representedwith") is in sp3 - hybrid state? .lal (cH),coH bl cqcocV3

(c) CH,C OOH (q cHlc ocl

13: Carbon with oxygen form s th ree types of oxidesi.e. carbon mono'oxide (CO), carbon dioxide(COr) and carlcon suboxide (CaOr). The exactstructure of CaO2 will be

(a)C:o-+C=C=6

(b)o=c=c:c=o(c)OiC=O--rC=O

(d) o -) o =C =C =C:14: The mmpoundswtlich do not contain covalent,

ionic aswell as co-ordinate bonds are(a) KCl, NaCl(b) H,sol' KcN(c) CuSO..sH,O, [[Fe(CN)J(d) Zeisel's salt and KCN

15: The correct order of decreasing polarisation ofions is

(a) Ci- < Br- > 1- > f.-(b);-= i- = B:- = cl-(c) i- > Ci- < 9r- > l-(d) :- > Br- > cl- > F-

'16: Which of the following sets of species is iso.steres?(a) NH3 and NHlt (b) NH..and CH.(c) CH. and H,O (d) NH3 and CH.

17: The concept of singlet bond (-) was given by(a) Pauling (b) Slater(c) Hund (d) Sugden

18: Number of sigma bonds, pi bonds and P - Pbonds in Proio respectively are

(a) 16r, 4;r, ZERO (b) 4c, 16r, 3

(c) 16o,2=,4 (d) 16q 4;,219: The mnecl order of bond-slrengths of bonds

formed by different types of overlapping is(a) ls-ls > ls-zs > 2eas> 2s-2p(b) lels < ls-2s < 2s-2s < 2s-2p(c) ls-2s < 1s-1s < 292p < 2s-2s(d) 2e2p < 2s-2s < ls-ls < ls-2s

20: The conecl increasing order of molecules inaccordance with number of lone pair ofelectrons on central-atoms is(a)XeFr< HrO< NH3 (b) XeF, < NH3 > HrO(c) NH3 < HrO < XeF, (d)HrO=XeFr=NH.

21: KF combines with HF to form KHF,, thecompound contains the species

(a) K., F and H. (b) K-, and F

(c) Kt and [HF, f (d) KHF- and F.

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22: The electronegativity of O, F, N , Cl and H are3.5,4.0, 3.2, 3.0 and 2.1 respectively, thestrongest bond willbe(a) F-o (b)O-Cl(c) N-H (d)O-H

23: Which of the following statements is conectlor CsBr"?(a) it is a covalent cc.ordinate compound

(b) it contains Cs* and Br- ions

(c) it contains Cs- and Bri ions

(d) it contains Cs- and B ions24: The common feature(s) among the species:

C.\--, CO and NO. idare(a) bond-order lhree and isoelec{ronics(b) bon4order tlrIo and isoelec{ronics

(c) boncl-order tvt/o and 6{igand acceptor

(d) isoelecironics and weak field liganda

25. The compound(s) which iJare although non-polar but having both polar and non-polar bonds.(a) qH6alone(b) CFLCOCH3 and CH3CHO

(c) CH3CI and CH,CI,(d) CH,CI, and CHCI3

26: The ortho, pala ard meta products of benzeneare shofln

xx

(t) (il) (il r)

(ortho) (m ela)

the conecl order of the dipole moments of theabove specieswill be(a) l> ll> lll (b) ll > l> lll(c) lll > ll > I (d) l> lll > ll

27: ln dichromate dianion r-o:1c)(a) 7 Cr- O bonds are equivalent(b) 6 Cr- O bonds are equivalent(c) 4 Cr-O bonds are equivalent(d) Ail Cr- O bonds are non-equivalent

28: The hybrid states of central atoms in NO:-, NO:

and NH:- are

(a) sp3, sd, sp3d respeclively(b) sp3, sf, sp3 respeclively(c) sp,, sp3, sp3 respectively(d) sp, sp2 and sp3 respectively

Y

(p a ra )

I

29: Valence bond theory was given by HeiUer andLondon and modified by.... ..... ..... .... ........(a) Pauling and Slater(b) Heitler and Pauling(c) Pauling and Mulliken(d) Pauling and Hund

30: ln a moleculeAB,, the central atom makes Z.B

- A - B = '105", the s-character in the hybridstatci of Awill be(a\'t't-'t2ok (bl2G21ok(c)31-32Yo (O 50-51oi6

31. Formal charge of an atom is defined as (FC =formal charge, VE = number of valenceeleclrons in free atom, BE = bonding eledrons,LPE = lone pair elec{rons)(a)FC=vE-BE-LPE

1(b) FC = ;vE - BE - LPE

1(c) FC = VE -:BE - LPE

1(d) FC = VE - BE -:LPE

32: The concept of hybridisation was given by(a) Pauling (b) Mulliken(c) Hund (d) lngold.

33: Which of the following sets of species doesnot follow odate.rule?(a) CO, PCls, PCl3, AICI3(b) Atcts' BF3' Pcts' sF6(c) CO, BrH6, NH", H,o(d) Hro, NHs, CO,, AtCl3

34: When two ice c bes are pressed over eacfioher, they unite to form one cube. Vvhich forceheld togetherthem?(a) hydrogen bond formation(b) Van der Waal's forces(c) mvdent attraction(d) dipole interac{ion

35: The carbonyl group has following resonatingstruclures

o (t) (tD\- \- + \^

. c-o )" u )t-othe conect order ofstability of these structuresis(a) l> ll> lll (b) I> lll> ll(c) t >t>ti (d)IIt >ll >I

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36: A dgma bond is formed up on tfie overlapping of(a) hybrid atomic orbitals(b) unhybrid domic orbitals(c) molecular orbitals(d) non-bonding orbitals

37: The compound that having 3c-2e bonds is(a) AlCl3 (b) Al,Cl6(c)8,{ (d) BF.

38: The species whose excited states are sameas ground states:(a) N, o (b) F, o(c) N, F (d) o, cl

39: The order of energies ofsp, sf and splhybridorbitals is (for the same principle quantumnumberofs and p orbitals)(a) sp < st' < sp3 (b)sp3<sf <sp(c) sp = sl = sp3 (d) sp3 < sp < sp'?

40: The hybrid states of carbon atoms in alleneCHr=C=CHrare(a) sp, st' (b) sp, sp3

(c) sf, spr (d) sp, sd, sp3

Answer1)a 2)a 3)a 4)c 5) d 6)b 7)bd 8)a 9)c 10)b

1'l)c 12)a 13)b '14)a 15)d 16)b 17)d 18)a 19)a 20)c21)c 22)d 23)c 24)a 25)a 26)d 27)b 28)d 29)a s0)b31)c 32)a 33)b 34)a 35)c 36)a 37)c 38)a 39)a 40)a

Ghemical bonding solution

l: (a) A water molecule can form 4 hydrogen bonds.

itf. -nr' 4-42 (a.) Bond-order ofBe, =

-=-=0'22

q (c) The resonating structure ofcor:- ions are

o\o/

o\,./- o <-----+

Bond-order ofC,E-4 -

) 2

3: (a)AlClr'5[O is an ionic cmpound.4 (c) C,, ; Fullerene

5: (d) The hybrid state ofl in ICI; is st'd. Thus, thestructure of ICI , will be trigonal bipyamidal.

6 (b) MOT was given by Multiken-Hund-7 (b), (d)

The srrucrure ofNCC and CS, are linear but SnCl2

and tlO have angular structure.

& (a) % ionic character with the help ofelecronegativity of atoms can be calculated by HS(Hanny-Smitb) Equatioo.

7o ionic character

= t6(x A- x R)+3.s(xn- xu)'z

Where X^ = EN ofless electronegative atom

=H=2.t... % ionic character ofHCl

= l6 (3.0 -2.1) + 3.5(3.0-2.1F= t4.4 +2.835: 17.235Y": l7o/o

.., Covalent character = 100- ionic character

= l0o-17:83%=83%

Ttnal number ofcharges -- 2e, whicl are distributedover three Gatoms.

2e.'. Charye on Gatom = TBond order ofC-O bond

total number of bonds between C and O

3

A--- I ?1

3

lO (b) The orbitals of equal energies are calleddeganerate orbitals. In a homonuclear moleculq

frzp, au,lrd t21,, are the orbitals ofequal energies,

2MOr\ 206

I C-Oot/

2013o

ll: (c) lr'=oC-C=o N(3o+4r)

tt (a\(cH3\coH

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I

I

CH"

cn-- J - oH'lCH,

Since, carbon (represerted with *) of

(CH|\C OH forms four sigma bonds, thus it

will be in spr hybrid state.

13: (b)O=C=C=C:9The structue of Crq is O) [most srmmetrical]

14. (a)

KCI and NaCl have only ionic bonds while FISQ,KCN, CuSQ'5rlo, K,[Fe(CI.|J andzeisel's salthave all the three qpes ofbonds.

15: (d) Acclrding to Fajan's rule 'the larger the anion,easier is the its polarisation'. Henct, the corectanswer is (d).

16 0)NH.- and CIl are isoelectronics ( I 0 eleckons) andhaving the same structue (as follou,s). Thus, thcyare iso-stcres.

17: (d) Sugden

l& (a)

The structurc ofP.Oro has 16o boncls,4z bmds,and no P-P bonds.

lq (a) Elecrons closer to the nucleus, stronger is thebond.

20 (c)N[ <rlO<XeF,

zt-* A. rrio-r'rhHN .' F.r.ir.. !a i...ir!l

[4.].lpH

o

llo

2l: (c)

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KttF2 -+ Kt +lHF2l22 (d) Boodsf€ngdr * difer€nce in electoneg.rivity

(AEIV) ofatoms.

rc: AEIV = 4-3.5 = 0-5

Hl : AEJV = 3.5 -3.0 = 0.5

N-H: Arg =3.2-2.4:0-8OiH: Arl/ = 3.5-2.4= l.l

A: (c)

CsBr, -+ Cst + Brr(tribromide ion)

24: (a) CN, CO and NO* have bond order three and are

isoclec'tronic species.

25. (a) Crt{ is a non-polar compound and having C{non-polar and C-H polar bonds. Due to plane ofsymmetry, its dipole moment becomes zero.

X: (d)

The order is o >m > p.

71: (b)

The structure ofdichomate dianion (CrrOr'-) is

The bonds (six) represented by e are equivalentand by n(2 bond) are ditrerent.

x: (d) lttQi = 5p ; NO; = sp2; NH; = sp3

29 (a) VBT was givcn by.Heitler and London and

modifed by Pauling and Slater.

30 (b) '.' cos 0 = j=

'.' cos105'= -.25t

.'..258 = s

s-l.'. s =.2058r, s=.2058x100=20.58%

131. (c) FC = VE-FE-LPE

32 (a) Pauling

33: (b)AlCl, BF,, PCI,, SF.

AlCl, BF! are eledron deficieut molecules whilePCl, and SF" having more than 8 electrons in thevalence shells ofP and S respectively.

c!

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34: (a) hydrogen bond formation35: (c) lll > I> II

The resonating structure with least or no charge isthe more stable. Thus, the structure III is themoststable. Among I and II, the stsucEue I is morc slablebccause, the dislribution ofcharges is natural i,e.more electronegative atom (O) has a -ve chargeand lessEN atom (C) hasa +ve charge.

36: (a) A sigma (o ) bond is always formed onoverlapping of hybrid o.bitals. Overlapping ofunhybrid orgbitals aMays results in the formationofpi( zr ) bond.

37: (c) B,Hu is called 3c-.2e (3 centes - 2 eleckons)compound bccause banana bonds having onlytwo electrons betwe€n lhree centres.

38: (a) N and O have the excited states same as theirground states.

3q (a) sp < st' < sp3

Greatcr the 7o pcharacter, higher the energl ofhybrid orbital-

,10 (a) sp, sp'?

C- I and C-3 form three o bonds, thus they are insplhybrid state, while C-2 forms two o bondsrhus it is in sp-h,6rid state.

IaPz

Itp

I