aieee chemistry questions

8/13/2019 AIEEE chemistry questions

1/15

1. How many unit cells are present in a cube-shaped ideal crystal of KCl of mass 1.00 g?(D (!

a ".01 # 10 "1

b $.1% # 10 "1

c &.0' # 10 "1

d %.0 # 10"1

Ans . D

Explanation :

". !nalysis shows that nic)el o*ide has the formula +i 0.,& 1.00 . How many atoms of nic)el e*ist as +iand +i ions? (H (+

a ,%/ %

b %/ ,%

c ,"/ &

d &/ ,"

Ans . !

Explanation


2/15

. f osmotic pressure of a solution ha2ing a solute of molar mass $0$00 g3mol is %.1$#10 -%atm at "00K/ calculate amount of solute in %00 ml of solution. (D (!

a 1.0$ g

b $.0$ g

c ".0" g

d 1.01 g

Ans . D

Explanation

%. f in a 4inc-sil2er cell/ concentration of sil2er ions is 0.015 and the cell potential measuredis 0.&&,$$2/ determine the concentration of 6n ions in the cell. (the differences in thepotential of the two electrodes is 0.&72 (D (!

a 10 -1 5

b 10-

5c 10 -$ 5

d 10 -' 5

Ans . C


3/15

Explanation

$. f rate constant of a 1 st order reaction is $.%& # 10 -1% s -1/ find out time needed to reducereactant to half of its 8uantity. (5 (!

a 1".7$ # 10 1" s

b '., # 10 -1% s

c &.0 # 10 -1% s

d 1"7.$ # 10 1" s

Ans . !

Explanation Half-life of a first order reaction t 13" 9 0.7, 3)/ where ) 9r ate constant 9 $.%& #10 -1% s -1. :o t 13" 9 0.7, 3 $.%& # 10 -1% s -1 9 1".7$ # 10 1" s.

7. ;hich of the below gi2en statement is true for the gi2en two reactions? (D (!


4/15

a Cu can be o*idi4ed by :n

b :n can be o*idi4ed by Cu

c Cu can be reduced by :n

d :n can be reduced by Cu

Ans . C

Explanation


5/15

d '.0' F5

Ans . F

Explanation:

10. Comple* Cr(H " %FrCl " is isolated as compound 1 and ". f compound 1 gi2es pale yellowprecipitates with !g+ that are soluble in concentrated ammonia/ which of the following iscompound 1? (D (+

a Cr(H" %Cl" Fr

b Cr(H" %FrCl Cl

c Cr(H" %Fr Cl"

d Cr(H" %Cl FrCl

Ans . !

Explanation: *idation number of Cr is in all comple*es. :o hybridi4ation of Cr +3 is d 2sp 3 whic

implies that co-ordination number of Cr +3 should be si* which is satisfied by compounds (a and(b . Gellow ppts. formed with !g+ 3 that are soluble in concentrated ammonia/ imply thatcompound 1 has bromide ions that react with !g+ 3 to form yellow ppts. of !gFr that are solublein concentrated ammonia.

11. dentify the chiral. (5 (C

a 1-chloropentane

b "-chloropentane

c -chloropentane


6/15

d -(1-chloromethyl pentane

Ans . F

Explanation: nly "-chloropentane has a carbon that has four different groups attached to it. :o"-chloropentane is a chiral.

1". ;hich of the below gi2en haloarene is most reacti2e? (D (!

a Chloroben4ene

b p-chloro nitroben4ene

c o/p-nitro chloroben4ene

d m-chloro nitroben4ene

Ans . C

Explanation: Ahe presence of nitro group at ortho- and para-positions withdraws the electrondensity from the ben4ene ring and thus facilitates the attac) of the +ucleophile on haloarene. Ahecarbanion thus formed is stabili4ed through resonance. Ahe negati2e charge appeared at ortho-

and para- positions with respect to the halogen substituent is stabili4ed by B+ " group while incase of meta-nitroben4ene/ none of the resonating structures bear the negati2e charge on carbonatom bearing the B+ " group. Aherefore/ the presence of nitro group at meta- position does notstabili4e the negati2e charge and no effect on reacti2ity is obser2ed by the presence of B+ " grouat meta-position.

1 . ;hich of the below gi2en reactions carried out in presence of acid is not correct? (5 (!

a %-methyl hept- -ene H " ------ %-methyl heptan-%-ol

b ent-1-ene H " ------ entan-"-ol

c %-methyl oct-%-ene H " ------ %-methyl octan-%-ol

d ent-"-ene H " ------ entan-"-ol

Ans . D

Explanation: !ddition of H " to al)enes follow 5ar)o2ni)o2 rule. :o H- is attached to longer

al)y chain. !lso stability of carbocations in their decreasing order is 0 " 0 1 0. :o ent-"-ene willyield pentan- -ol and not pentan-"-ol.

1%. n which pair of reactions does each reaction not yield Fen4aldehyde? (5 (C

a Iosemund reduction/ :tephen reaction

b =atterman Koch reaction/ Jtard reaction

c :tephen reaction/ Jtard reaction

d Iosemund reduction/ Eriedel Crafts acylation

Ans . D

Explanation: Iosemund reduction/ :tephen reaction/ =atterman Koch reaction and Jtardreaction are four different reactions that yield ben4aldehyde. Eriedel crafts acylation is reaction ofben4ene with acid chloride that yields )etone.


7/15

1$. !cidity of -hydrogen of carbonyl compounds is due to (5 (C

a :trong electron withdrawing effect of carbonyl group

b Iesonance stabili4ation of the conLugate base

c (a M (b both

d +either (a nor (b

Ans . CExplanation: Ahe acidity of -hydrogen atoms of carbonyl compounds is due to the strongelectron withdrawing effect of the carbonyl group and resonance stabili4ation of the conLugatebase.

17. ;hich compound has highest boiling point? (D (+

a n-C %H , +H "

b n-C %H , H

c C" H$CH(CH "

d C" H$+(CH "

Ans . F

Explanation: Compounds (c and (d do not form intermolecular H-bonding. :o their boiling pointsare lower than that of (a and (b which form intermolecular H-bonding. !lso/ is moreelectronegati2e element than +. :o -H bond is more polar than +-H bond. :o strongerintermolecular H-bonds are formed in compound (a than in (b . :o compound (a has higherboiling point than (b / and hence it has highest boiling point among the four compounds.

1'. ;hich of the below gi2en is the most basic compound? (5 (!

a +(CH (g

b +H(CH " (g

c +H " (CH (g

d +H (g

Ans . !

Explanation: Due to the electron releasing nature of al)yl group/ it (I pushes electrons towardsnitrogen and thus ma)es the unshared electron pair more a2ailable for sharing with the proton ofthe acid. 5oreo2er/ the substituted ammonium ion formed from the amine gets stabili4ed due todispersal of the positi2e charge by the effect of the al)yl group. Hence/ al)yl amines are strongerbases than ammonia. Ahus/ the basic nature of aliphatic amines should increase with increase inthe number of al)yl groups. Ahis trend is followed in the gaseous phase. Ahe order of basicity ofamines in the gaseous phase follows the e*pected order tertiary amine secondary amine primary amine +H .

1&. ;hich of the following is not a type of I+! molecule? (J (K


8/15

a messenger-I+!

b ribosomal-I+!

c chromosomal-I+!

d transfer-I+!

Ans . C

Explanation: I+! molecules are of three types and are named as messenger I+! (m-I+! /ribosomal I+! (r-I+! and transfer I+! (t-I+! .

1,. Awo strands of D+! are complementary to each other because N (D (!

a H-bonds are formed between specific pair of bases

b H-bonds are formed between identical pair of bases

c H-bonds are formed between different pair of bases

d :tructure of the two strands is same

Ans . !

Explanation: Awo nucleic acid chains are wound about each other and held together by hydrogenbonds between pairs of bases. Ahe two strands are complementary to each other because thehydrogen bonds are formed between specific pairs of bases. !denine forms hydrogen bonds withthymine whereas cytosine forms hydrogen bonds with guanine.

"0. ;hich of the below gi2en does not hold true for fibers? (J (K

a Ahey are thread forming solids

b Ahey are polymers with wea)er intermolecular forcesc Aheir inter molecular forces are due to H-bonding or dipole-dipole interaction

d Ahey ha2e high melting points

Ans . F

Explanation: Eibers are the thread forming solids which possess high tensile strength and highmodulus. Ahese characteristics can be attributed to the strong intermolecular forces li)e hydrogenbonding. Ahese strong forces also lead to close pac)ing of chains and thus impart crystallinenature. Ahey ha2e high melting points. Ahe e*amples are polyamides (nylon 7/ 7 / polyesters

(Aerylene / etc.

"1. ;hy are the receptors selecti2e towards chemical messengers? (5 (C

a Aheir binding sites ha2e different shape and amino acid composition

b Aheir binding sites ha2e different shape and structure

c Aheir binding sites ha2e different structure and amino acid composition

d Aheir binding sites ha2e different shape/ structure and amino acid composition

Ans . D


9/15

Explanation: Ieceptors show selecti2ity for one chemical messenger o2er the other because theirbinding sites ha2e different shape/ structure and amino acid composition.

"". Density of m solution of CaCl 2 is 1."$g3m@. Calculate its molarity. (H (!

a ".&1 moles3liter

b 1.077% moles 3liter

c " moles3liter

d 1. moles3liter

Ans . !

Explanation:

" . Kinetic energy of an electron emitted when radiation hits metal is ".%"%#10 -18 O. f the thresholdfre8uency of the metal is '." # 10 1$/ find the fre8uency of the radiation. (D (!

a %.0, # 10 16 sec -1

b .0, # 10 16 sec -1

c 1.0, # 10 16 sec -1

d ".0, # 10 16 sec -1

Ans . C


10/15

Explanation:

"%. !rrange the below gi2en elements in their increasing order of ioni4ation energy. (5 (! :/ / E/ Cl

a :>Cl> >Eb :> >Cl>E

c E>Cl> >:

d E> >Cl>:

Ans . !

Explanation: J increases across a period and decreases along a group. :o E has highest M :has lowest J among the four elements. 5oreo2er/ belongs to second 8uantum and Cl belongsto third 8uantum. :o electrons in Cl atom are better shielded than in atom and hence they canbe easily remo2ed. :o < iH(O) < iH(Cl) . :o elements with increasing J are :>Cl> >E.

"$. ;hich compound does not ha2e intramolecular H-bonding? (D (!

a o-amino phenol

b o-hydro*y ben4aldehyde

c o-hydro*y ben4oic acid

d p-amino phenol

Ans . D


11/15

Explanation: Compounds (a / (b and (c / each ha2e a B H group at ortho position. H atom of BH group forms H-bond with + atom of amino group of same molecule in compound (a . !nd H

atom of B H group forms H-bond with atom of carbonyl group of same molecule in compounds(b and (c . :o all these three e*hibit intramolecular H-bonding. p-aminophenol e*hibitintermolecular H-bonding between H atom of B H group of one molecule and + atom of aminogroup of another molecule.

"7. f at " bar pressure a mi*ture of o*ygen/ nitrogen and hydrogen gases contains %0P " / %"P + " and 1&P H " / calculate partial pressure of nitrogen gas. (D (!

a 0.1"& bar

b 1.$% bar

c 0."7 bar

d 0."0 bar

Ans . C

Explanation:


12/15

"'. Combustion of % moles of ammonia release 1$17 )O of heat and combustion of " moles ofhydrogen gas release $'" )O of heat. Calculate the enthalpy change for formation of ammonia.

(D (+a $0 )O

b 100 )O

c "00 )O

d 77.77 )O

Ans. !

Explanation:

"&. Consider the following reactions and find out K $. (H (+

!Q F; K 19 "

F; CR K "9

CR DG K 9%

DG J6 K %9$

!Q J6 K $9??

a 1%

b 70

c 1"0


13/15

d "&

Ans. C

Explanation:

",. ;hich reaction is not a redo* reaction? (5 (!

a

b

c

d

Ans. F

Explanation: Ahere is no change in the o*idation number of sodium/ carbon and o*ygen ine8uation (b as shown below. :o it is not a redo* reaction.

0. ;ith which of the following method permanent hardness of water cannot be remo2ed?(J (K


14/15

a CalgonSs method

b on e*change method

c :ynthetic resins method

d Areatment with caustic soda

Ans. D

Explanation: Hardness of water cannot be remo2ed with treatment with caustic soda (+a H butcan be remo2ed using washing soda (+a 2C 3 .

1. dentify the correct statement with respect to @ithium. (5 (K

a t combines with e*cess of o*ygen to form supero*ide

b t is least reacti2e but strongest reducing agent among all the al)ali metals

c t reacts with ethyne

d t forms solid hydrogen-carbonate

Ans. F

Explanation: @ithium hydrogen-carbonate is not obtained in the solid form. @ithium unli)e otheral)ali metals forms no ethynide on reaction with ethyne. Ahe o*ides/ @i 2 and 5g do not combinewith e*cess o*ygen to gi2e any supero*ide. @ithium is least reacti2e but the strongest reducingagent among all the al)ali metals.

". *ide of which element is co2alent in nature? (D (C

a Fa

b Ca

c 5g

d Fe

Ans. D

Explanation: Ahe al)aline earth metals burn in o*ygen to form the mono*ide/ 5 which/e*cept for Fe / ha2e roc)-salt structure. Ahe Fe is essentially co2alent in nature.

. ;hich allotrope of carbon is the hardest natural substance )nown? (J (C

a =raphite

b Coal

c Diamond

d Eullerenes

Ans. C


15/15

Explanation: t is 2ery difficult to brea) e*tended co2alent bonding in diamond and/therefore/ it is a hardest substance on the earth.

%. ;hich acid is not present in acid rain? (5 (!

a :ulphuric acid

b :alicylic acid

c +itric acid

d Carbonic acid

Ans. F

Explanation: :alicylic acid is organic compound whereas other three are inorganicformed during rain by reaction of water with C 2(g / : 2(g and + 2(g present in air.: 2(g and + 2(g after o*idation and reaction with water are maLor contributors to acidrain/ because polluted air usually contains particulate matter that cataly4e the o*idation.

$. ;hich compound is formed on action of iodine on ethyl alcohol in the presence of al)ali?

(5 (+a Jthane

b Jthyl iodide

c :odium iodide

d odoform

Ans. D

Explanation: odoform is prepared in the laboratory by the action of iodine on ethylalcohol or acetone/ in the presence of al)ali. Ahis is called haloform reaction.

aieee chemistry questions

Documents