SELECT THE CORRECT ALTERNATIVE (ONLY ONE CORRECT ANSWER)

1 . For a catalyst which condition is not essential :

(A) Variable valency (B) High ionisation energy

(C) Empty orbitals (D) Free valency on the surface

2 . Which element is having lowest melting and boiling point :

(A) Ti (B) Cu (C) Zn (D) Mn

3 . Density of which of the following element is highest :

(A) Pt (B) Hg (C) Mn (D) Cu

4 . The adsorption of hydrogen by platinum black is called :

(A) hydrogenation (B) Reduction (C) Occlusion (D) Hydration

5 . To which of the following series the transition element from Z = 39 to Z = 48 belong :

(A) 3d series (B) 4d series (C) 5d series (D) 6d series

6 . Permanent magnets are generally made of alloys of :

(A) Co (B) Zn (C) Mn (D) Pb

7 . The reaction of O2 and CO with haemoglobin gives :

(A) Only oxygen-haeme complex

(B) Only CO-haeme complex

(C) Both but oxygen-haeme-complex is more stable

(D) Both but CO-haeme-complex is more stable

8 . Which of the following statement is not correct :

(A) Fe, Ni, Co form interstetial compound

(B) CuSO4 + Ca(OH)2 is called Bordeaux mixture

(C) Verdigris is basic copper acetate [Cu(COOCH3)2Cu(OH)2]

(D) 24 carat gold is an alloy of Au and Cu

9 . Chromium forms most stable compound in the following oxidation state :

(A) Cr (I) (B) Cr (II) (C) Cr (III) (D) Cr (iv)

1 0 . Not more than one oxidation state is show by :

(A) Mn (B) Cr (C) Fe (D) Sc

1 1 . Which pair of ions is colourless :

(A) Mn+3, CO+3 (B) Fe3+, Cr+3 (C) Zn2+, Sc3+ (D) Ti2+, Cu2+

1 2 . Which of the following set of metals can form alloy :

(A) Cu – Au (B) Li–Na (C) Fe–Hg (D) All

1 3 . Which of the following is ferromagnetic :

(A) Cu, Ag, Au (B) Fe, Co, Ni (C) Zn, Cd, Hg (D) Ca, Sr, Ba

1 4 . The number of moles of acidified KMnO4 required to convert sulphite ion into sulphate ion is :

(A) 2/5 (B) 3/5 (C) 4/5 (D) 1

EXERCISE-01 CHECK YOUR GRASP

1 5 . N2(g) + 3H2(g) Fe + Mo

2NH3(g); Haber's process, Mo is used as :

(A) A catalyst (B) A catalytic promoter

(C) An oxidising agent (D) As a catalytic poison

1 6 . 22 7Cr O

X

Y 2

42CrO , X and Y are respertively :

(A) X = OH–, Y = H

+(B) X = H

+, Y = OH

–

(C) X = OH–, Y = H2O2 (D) X = H2O2, Y = OH

–

1 7 . The magnetism of Ni2+ ion is :

(A) eh

4 m(B)

eh6

4 m

(C) eh

84 m

(D) eh

104 m

1 8 . During estimation of oxalic acid Vs KMnO4, self indicator is :

(A) KMnO4 (B) Oxalic acid (C) K2SO4 (D) MnSO4

1 9 . Bayer's reagent used to detect olifinic double bond is :

(A) Acidified KMnO4 (B) Aqueous KMnO4

(C) 1% alkaline KMnO4 solution (D) KMnO4 in benzene

2 0 . Cu+ conc. HNO3 Cu(NO3)2 + X (oxide of nitrogen); then X is :

(hot)

(A) N2O (B) NO2 (C) NO (D) N2O3

2 1 . The higher oxidation states of transition elements are found to be the combination with A and B, which are:

(A) F, O (B) O, N (C) O, Cl (D) F, Cl

2 2 . Manganese steel is used for making railways because :

(A) It is hard with high percentage of Mn

(B) It is soft with high percentage of Mn

(C) It is hard with small concentration of manganese with the impurities

(D) It is soft with small concentration of manganese with impurities.

2 3 . 'Bordeaux mixture' is used as a fungicide. It is a mixture of :

(A) CaSO4 + Cu(OH)2 (B) CuSO4 + Ca(OH)2

(C) CuSO4 + CaO (D) CuO + CaO

2 4 . Anhydrous ferric chloride is prepared by :

(A) heating hydrated ferric chloride at a high temperature in a stream of air

(B) heating metallic iron in a stream of dry chlorine gas

(C) reaction of ferric oxide with HCl (aq)

(D) reaction of metallic iron with HCl (aq)

2 5 . The product of oxidation of I– with MnO4

– in alkaline medium is :

(A) IO3– (B) I2 (C) IO– (D) IO4

–

2 6 . Copper becomes green when exposed to moist air for longer period.

(A) Because of the formation of a layer of cupric oxide on the surface of copper

(B) Because of the formation of a layer of basic carbonate of copper on the surface of copper

(C) Because of the formation of a layer of cupric hydroxide on the surface of copper.

(D) (A) and (C) both

2 7 . CuFeS2 + O2 (excess) X(s) + Y(s) (Unbalanced Equation) :

Which is correct choice for (X) and (Y) ?

(A) (X) liberates iodine from soluble iodides like KI

(B) (Y) on heating liberates SO3 only

(C) (X) forms bluish white ppt. with sodium hydroxide which redissolves in excess of sodium hydroxide.

(D) (Y) on reaction with potassium ferricyanide gives brown ppt.

2 8 . FeCl3.6H2O + C(CH3)2 (CH3O)2 Products

Reaction products are

(A) FeCl3, CH3OH and CH3COCH3 (B) (CH3O)3Fe, HCl and H2O

(C) FeCl2, HCl and CH3COCH3 (D) Fe(OH)3, FeCl3 and CH3COCH3

2 9 . Which of the following statements is incorrect ?

(A) Transition element exhibit higher enthalpies of atomization as they have stronger interactomic interaction

(B) IE2 of 23V < 24Cr > 25Mn and 28Ni < 29Cu > 30Zn

(C) Ni (II) compounds are more stable than pt(II) where as pt(IV) compounds are more stable than Ni (IV)

(D) The elements which gives the greatest number of oxidation states does not occur in or near the middle of

the series

3 0 . Stability of Cu+ and Ag+ halide complexes are in order :

(A) I > Br > Cl > F (B) F > Cl > Br > I (C) Cl > F > I > Br (D) Br > I > Cl > F

3 1 . When KI (excess) is added to :

I : CuSO4 II. HgCl2 III. Pb(NO3)2

(A) A white ppt. of CuI in I, an orange ppt. HgI2 in II and a yellow ppt. of PbI2 in III

(B) A white ppt. of CuI in I, an orange ppt. dissolving to HgI42– in II, and a yellow ppt. of PbI2 in III

(C) A white ppt. of CuI, HgI2 and PbI2 in each case

(D) none is correct

3 2 . CuSO4 can be estimated volumetrically :

(A) by reaction with KI followed by reaction with Na2S2O3

(B) by reaction with BaCl2

(C) by reaction with K4[Fe(CN)6]

(D) none is correct

3 3 . Cl2 gas is obtained by various reactions but not by :

(A) KMnO4 + conc. HCl (B) KCl + K2Cr2O7 + conc. H2SO4

(C) MnO2 + conc. HCl (D) KCl + F2

3 4 . Maximum magnetic moment is shown by :

(A) d5 (B) d6 (C) d7 (D) d8

3 5 . A jeweller is selling 22-carat gold articles with 95% purity, it is approximately :

(A) exact (B) 3.5% higher (C) 3.5% lower (D) 5% lower

3 6 The basic character of the transition metal monoxides follows the order :

(Atomic no. Ti = 22, V = 23, Cr = 24, Fe = 26)

(A) TiO > FeO > VO > CrO (B) TiO > VO > CrO > FeO

(C) VO > CrO > TiO > FeO (D) CrO > VO > FeO > TiO

3 7 . AgCl on fusion with sodium carbonate, gives :

(A) Ag2CO3 (B) Ag2O (C) Ag (D) Ag2C2

3 8 . Which of the following reactions is used to estimate copper volumetrically ?

(A) 2Cu2+ + 4CN– Cu2(CN)2 + (CN)2

(B) Cu2+ + 4NH3 [Cu(NH3)4]2+

(C) 2Cu2+ + 2CNS– + SO2 + 2H2O Cu2(CNS)2 + H2SO4 + 2H+

(D) 2Cu2+ + 4I– Cu2I2 + I2

3 9 . Atomic size of gold is almost the same as that of silver. It is due to :

(A) the same crystal structure of silver and gold

(B) almost the same electropositive character of the two metals

(C) transition metals contraction in a series

(D) the effect of lanthanide contraction

4 0 . Which of the following compounds is most sensetive of light ?

(A) AgCl (B) AgCN (C) AgI (D) AgBr

Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Ans . B C A C B A D D C D C A B A B

Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Ans . A C D C B A A B B A B A A A A

Que. 31 32 33 34 35 36 37 38 39 40

Ans . B A B A B B C D D D

EXERCISE-1ANSWER KEYCHECK YOUR GRASP

SELECT THE CORRECT ALTERNATIVES (ONE OR MORE THEN ONE CORRECT ANSWERS)

1 . An inorganic salt is lemon yellow in colour. It becomes orange in colour like methyl orange when it is acidic

and again becomes yellow when it is alkaline. The inorganic salt will be :

(A) Copper nitrate (B) Ferric chloride

(C) Potassium chromate (D) Potassium ferri cyanide

2 . Magnetic moment 35 is true for which of the following pair :

(A) Co+2, Fe+2 (B) Fe+3, Mn+2 (C) Co+3, Cr+2 (D) Fe+2, Mn+2

3 . Fe+3 is more stable than Fe+2, the reason is/are :

(A) Ist and IInd I.P. difference is less than 11.0 eV

(B) Core of Fe+3 is more stable

(C) IInd and 3nd IP difference is less than 11.0 eV

(D) IP of Fe+3 is high

4 . Addition of non-metals like B and C to the interstitial sites of a transition metal results the metal :

(A) of more ductability (B) of less ductability

(C) Less malleable (D) of more hardness

5 . The metal(s) which does/do not form amalgam is/are :

(A) Fe (B) Pt (C) Zn (D) Ag

6 . Correct statement(s) is/are :

(A) An acidified solution of K2Cr2O7 liberates iodine from KI

(B) K2Cr2O7 is used as a standard solution for estimation of Fe2+ ions

(C) In acidic medium, N = M/6 for K2Cr2O7

(D) (NH4)2Cr2O7 on heating decomposes to yield Cr2O3 through an endothermic reaction

7 . The highest oxidation state shown by transition element is :

(A) + 7 by Mn (B) + 8 by Os (C) + 8 by Ru (D) + 7 by Fe

8 . A compound of mercury used in cosmetics, in Ayurvedic and Yunani medicines and known as Vermilon is :

(A) HgCl2 (B) HgS (C) Hg2Cl2 (D) HgI

9 . Acidified chromic acid + H2O2 X + Y, X and Y are :

(Blue colour)

(A) CrO5 and H2O (B) Cr2O3 and H2O

(C) CrO2 and H2O (D) CrO and H2O

1 0 . Y(g) KI CuSO4 X(Blue colour), X and Y are :

(A) X = I2, Y = [Cu(H2O)4]2+ (B) X = [Cu(H2O)4]2+, Y = I2

(C) X = [Cu(H2O)4]+, Y = I2 (D) X = [Cu(H2O)5]2+, Y = I2

1 1 . (NH4)2Cr2O7 (Ammonium dichromate) is used in fire works. The green coloured powder blown in air is :

(A) Cr2O3 (B) CrO2 (C) Cr2O4 (D) CrO3

EXERCISE–02 BRAIN TEASERS

1 2 . Iron becomes possive by.............due to formation of..................... :

(A) dil. HCl, Fe2O3 (B) Aqua-regia, Fe3O4

(C) conc. H2SO4, Fe3O4 (D) conc. HCl, Fe3O4

1 3 .

+ xe MnO– 4

2–

+ ye (Acidic medium)–

+ ze (Natural medium)–

MnO2

Mn+2

MnO4

–

x, y and z are respectively :

(A) 1, 2, 3 (B) 1, 5, 3 (C) 1, 3, 5 (D) 5, 3, 1

1 4 . In the equation : M + 8 CN– + 2H2O + O2 4[M(CN)2]

– + 4OH

–, metal M is :

(A) Ag (B) Au (C) Cu (D) Hg

1 5 . Amongst CuF2, CuCl2 and CuBr2 :

(A) Only CuF2 is ionic

(B) Both CuCl2 and CuBr2 are covalent

(C) CuF2 and CuCl2 are ionic but CuBr2 is covalent

(D) CuF2, CuCl2 as well as CuBr2 are ionic

1 6 . A metal M which is not affected by strong acids like conc. HNO3, conc. H2SO4 and conc. solution of alkalies

like NaOH, KOH forms MCl3 which finds use for toning in photography. The metal M is :

(A) Ag (B) Hg (C) Au (D) Cu

1 7 . CuSO4(aq.) + 4NH3 X, then X is :

(A) [Cu(NH3)4]2+ (B) Paramagnetic

(C) Coloured (D) Of a magnetic moment of 1.73 BM

1 8 . Number of moles of SnCl2 required for the reduction of K2Cr2O7 into Cr2O3 is (in acidic medium) :

(A) 3 (B) 2 (C) 1 (D) 1/3

1 9 . Acidified KMnO4 can be decolourised by :

(A) SO2 (B) H2O2 (C) FeSO4 (D) FeCl3

2 0 . The Ziegler-Natta catalyst used for polymerisation of ethene and styrene is TiCl4 + (C2H5)3Al, the catalysing

species (active species) involved in the polymerisation is :

(A) TiCl4 (B) TiCl3 (C) TiCl2 (D) TiCl

2 1 . Which of the following raction is possible at anode?

(A) 2Cr3+ + 7H2O 2–2 7Cr O + 14H

+(B) F2 2F

–

(C) 2

1O

2 + 2H

+ H2O (D) None of these

2 2 . Colourles solution of the following four salts are placed separately in four different test tubes and a strip of

coper is dipeed in each one of these. Which solution will turn blue?

(A) KNO3 (B) AgNO3 (C) Zn(NO3)2 (D) ZnSO4

2 3 . Cuprous chloride is obtained from cupric chloride :

(A) By heating cupric chloride with chlorine

(B) By the electrolysis of cupric chloride containing HCl

(C) By heating cupric chloride with conc. HCl and copper turnings

(D) By passing H2 over CuCl2

2 4 . When excess of sodium thiosulphate is added to dil. AgNO3 solution a soluble compound X is formed.

However, when dil. Na2S2O3 solution is addeed to conc. AgNO3 solution a white ppt. turning yellow and

finally black ppt. of Y is obtained. Which is correct pair. :

(A) X is Ag2S and Y is Na3[Ag(S2O3)2]

(B) X is Na3[Ag(S2O3)2] and Y is Ag2S

(C) X is Ag2S2O3 and Y is Ag2S

(D) X is Ag2S2O3 and Y is Na3[Ag(S2O3)2]

2 5 . Carat is a measure of :

(A) Impure gold (B) Purity of gold

(C) Pure gold (D) None of these

2 6 . Fulminating gold is :

(A) CuFeS2 (B) FeS2

(C) Au(NH2) = NH or AuN2H3 (D) AuCl3

2 7 . In the reaction HgCl2 + 4KI A + 2KCl, A is :

(A) HgI2 (B) K2HgI3 (C) K2HgI4 (D) KHgI3

2 8 . Iodide of Millon's base is :

(A) K2[HgI4] (B) Hg

NH2

O—Hg—I

(C) [Hg2O.NH2OH].H2O (D) Hg(NH2) I + Hg

2 9 . The following reaction describes the rusting of iron,

4Fe + 3O2 4Fe3+ + 6O2–. Which one of the following statements is incorrect :

(A) This is an example of a redox reaction

(B) Metallic iron is reduced to Fe2+

(C) Fe3+ is an oxidising agent

(D) Metallic iron is a reducing agent

3 0 . Which of the following chemical reaction(s) is (are) involved in the developing of photographic plate ?

(A) C6H4(OH)2 + 2AgBr 2Ag + C6H4O2 + 2HBr

(B) AgBr + 2Na2S2O3 Na3[AgS2O3)2] + NaBr

(C) AgBr + 2NH3(aq) [Ag(NH3)2] Br

(D) 2AgBr + Na2S2O3 Ag2S2O3 + 2NaBr

3 1 . Which of the following statement(s) is (are) not correct with reference to ferrous and ferric ions

(A) Fe3+ gives brown colour with potassium ferricyanide

(B) Fe2+ gives blue ppt with potassium ferricyanide

(C) Fe3+ gives red colour with potassium sulphocyanide

(D) Fe2+ gives brown colour with potassium sulphocyanide

3 2 . KMnO4 on treatment with conc. H2SO4 forms a compound (X) which decomposes explosively on heating

forming (Y). The (X) and (Y) are respectively :

(A) Mn2O7, MnO2 (B) Mn2O, Mn2O3 (C) MnSO4, Mn2O3 (D) Mn2O3, MnO2

3 3 . The hydrated cupric chloride is strongly heated. Which of the following statement(s) is (are) correct for this :

(A) It is reduced to Cu2Cl2 (B) Cupric oxide is formed along with Cu2Cl2

(C) Only Cl2 is liberated (D) Cl2 and HCl both are liberated

3 4 . Select the incorrect statement(s) :

(A) In K2MnO4 and CrO2Cl2, The central transition metals/ions have the same oxidation state.

(B) Both sodium and potassium dichromate can be used as primary standard in volumetric estimations.

(C) Potassium dichromate on strong heating evolves oxygen gas and forms green powder.

(D) Potassium permangnate on heating with solid KOH evolves oxygen gas and forms a black powder.

3 5 . Cuprous chloride can not be prepared :

(A) by passing SO2 through the solution containing CuSO4 and NaCl

(B) by heating excess of copper with conc. HCl in presence of a little KClO3

(C) by boiling copper sulphate solution with excess of copper turnings in presece of hydrochloric acid

(D) by dissolving cupric oxide or copper carbonate in conc. HCl

3 6 . Which of the following ion is not coloured ?

(A) Ni(DMG)2 (B) [Co(SCN)4]2– (C) [Fe(H2O)5SCN]2+ (D) [Al(OH)4]–

3 7 . The total spin and paramagnetism (B.M.) of ferrocyanide ion are respectively :

(A) 0, 2 6 (B) 5 / 2, 35 (C) 2, 24 (D) 1, 2 2

3 8 . Which is not correct about FeO0.94 ?

(A) It is non-stoichiometric compound

(B) Some of Fe2+ ions get replaced by as many two third Fe3+ ions

(C) It is metal excess solid

(D) It is metal deficient solid.

3 9 The transition metal used in X-rays tube is :

(A) Mo (B) Ta (C) Tc (D) Pm

4 0 . The reagent used in the gravimetric annalysis of Co2+ ion is :

(A) DMG (B) -nitro--nephthol (C) -nitro--nephthol (D) K4[Fe(CN)6]

Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Ans . C B B, C B,C,D A,B A,B,C B,C B B B A B B B A,B

Que. 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Ans . C A,B,C,D A A,B,C B A B C B B C C B B A,B

Que. 31 32 33 34 35 36 37 38 39 40

Ans . D A A,B,D B,D D D C C A B

EXERCISE-2ANSWER KEYBRAIN TEASERS

TRUE / FALSE

1 . Fe3O

4 is mixed oxide of FeO and Fe

2O

3.

2 . Acidic potassium permanganate is used in organic chemistry under the name Baeyer's reagent.

3 . Cast iron has the maximum percentage of carbon.

4 . No rusting takes place in absence of moisture.

5 . Silver is found in nature both in native and combined state.

6 . Copper dissolves in hydrochloric acid.

FILL IN THE BLANKS

1 . ..............................ion show maximum paramagnetic character among the bivalent ions of first transitionon series.

2 . The salts ......................... and ......................... are isostructural (FeSO4.7H

2O, CuSO

4.5H

2O, MnSO

4.4H

2O,

ZnSO4.7H

2O)

3 . Which one of the following CuCl2, CaCl

2 or CdCl

2 is paramagnetic in character .........................

4 . The chromate ion in acidic medium changes to ......................

5 . Among the ion, Sc3+, V3+ and Cr3+, the ion that gives colourless compound is........................

MATCH THE COLUMN

1 . Column-I (Metals ) Column-II (Ores)

(A) Zn (p) Cyanide process

(B) Cu (q) hydrometallurgical process

(C) Ag (r) roasting

(D) Pt (s) brass.

2 . Column-I (Al loys) Column-II (Consti tuents)

(A) TiCl4

(p) Adams catalyst in reduction

(B) PdCl2

(q) In preparation of (CH3)2 SiCl

2

(C) Pt/PtO (r) Used as the Natta catalyst in polythene production

(D) Cu (s) Wake process for converting C2H

4 to CH

3CHO

ASSERTION & REASON QUESTIONS

These questions contains, Statement-I (assertion) and Statement-II (reason).

(A) Statement-I is True, Statement-II is True ; Statement-II is a correct explanation for Statement-I

(B) Statement-I is True, Statement-II is True ; Statement-II is NOT a correct explanation for Statement-I

(C) Statement-I is True, Statement-II is False.

(D) Statement-I is False, Statement-II is True.

1 . S ta tement - I : General formula of transition element is (n – 1)d1–10 ns1–2

Be c au s e

Statement - I I : Transition element have 10 electrons in (n–1)d orbitals.

EXERCISE–03 MISCELLANEOUS TYPE QUESTIONS

2 . S ta tement - I : 1st ionisation potential of mercury is greater than cadmium.Be c au s eStatement - I I : Hg has stable electronic configuration (5d10 6s2).

3 . S ta tement - I : Cu+ is more stable than Cu+2.Be c au s eStatement - I I : IP is greater than 16 eV

4 . S ta tement - I : AgI is coloured while AgF is colourless.Be c au s eStatement - I I : Unpaired electron is present in AgI

5 . S ta tement - I : Change in colour of acidic solution of potassium dichromate by breath is used to testdrunk drivers.

Be c au s eStatement - I I : Change in colour is due to the complexation of alcohol with potassium dichromate.

6 . S ta tement - I : K2CrO4 has yellow colour due to charge transfer.Be c au s e

Statement - I I : 24CrO ion is tetrahedral in shape.

7 . S ta tement - I : CrO3 reacts with HCl to form chromyl chloride gas.Be c au s eStatement - I I : Chromyl chloride (CrO2Cl2) has tetrahedral shape.

8 . S ta tement - I : Zinc does not show characteristic properties of transition metals.Be c au s eStatement - I I : In zinc outermost shell is completely filled

9 . S ta tement - I : Equivalent mass of KMnO4 is equal to one-third of its molecular mass when it acts as anoxidising agent in an alkaline medium.

Be c au s eStatement - I I : Oxidation nhumber of Mn is +7 in KMnO4

COMPREHENSION BASED QUESTIONS

Comprehens ion # 1

Hg shows two oxidation states (I) and (II) in its compounds. Chemistry of Hg(I) in intersting as Hg+ does not

exist. It has been proved on the basis of magnetic moment determination and equilibrium studies on Hg(I)

and Hg(II) salts. It is intersting to note that Hg(I) salts are diamagnetic, yet Hg+ contains unpaired electron. In

solutions 22Hg disproportionates as : 2

2Hg Hg() + Hg2+, but equilibrium constant is very low. But

when anions like S2– are added the formation of insoluble HgS promotes the disproportionation. The same

reason is used to explain non-existance of some mercurous salts.

1 . The equilibrium established when HgCl2 is shaken with excess of Hg is :

(A) Hg2+ + Hg 2Hg+ (B) Hg2+ + Hg() 22Hg

(C) Hg + 2Hg2+ Hg2+ + 2Hg+ (D) No equilibrium is established

2 . In an experiment when placed in weak magnetic field, calomel was slightly repelled by the magnetic field.

This experimental observation suggests that :

(A) Hg+ ion has no unpaired electron

(B) Mercurous ion has formula 22Hg instead of Hg+

(C) This experimental observation is not correct and actually mercurous salts are paramagnetic due to 6s

unpaired electron

(D) Sometimes mercurous ion may exist as 22Hg

3 . Which is well known compound :

(A) Hg2S (B) Hg2O (C) Hg2Cl2 (D) All of the above

4 . Hg2Cl2 on treatment with alkali gives red solid which is :

(A) Hg2O (B) HgO (C) Hg2(OH)2 (D) Hg(OH)2

Comprehens ion # 2

Transition metal and their compounds are used as catalysts in industry and in biological system. For example,

in the Contact process, vanadium compounds in the +5 state (V2O

5 or –

3VO ) are used to oxidise SO2 to SO

3:

SO2 +

1

2O

2

V O2 5 SO

3

It is thought that the actual oxidation process takes place in two stages. In the first step, V5+ in the presence

of oxide ions converts SO2 to SO

3. At the same time, V5+ is reduced to V4+.

2V5+ + O2– + SO2 2V4+ + SO

3

In the second step, V5+ is regenerated from V4+ by oxygen :

2V4+ + 1

2O

2 2V5+ + O2–

The overall process is, of course, the sum of these two steps:

SO2 +

1

2O

2 SO

3

1 . Transition metals and their compounds catalyse reactions because :

(A) They have competely filled s-subshell

(B) They have a comparable size due to poor shielding of d-subshell

(C) They introduce an entirely new reaction mechanism with a lower activation energy(D) They have variable oxidation states differ by two units

2 . During the course of the reaction :

(A) Catalyst undergoes changes in oxidation state

(B) Catalyst increases the rate constant

(C) Catalyst is regenerated in its orginal form when the reactants form the products

(D) All are correct.

3 . Catalytic activity of transition metals depends on :

(A) Their ability to exist in different oxidation states

(B) The size of the metal atoms

(C) The number of empty atomic orbitals available

(D) None of these

4 . Which of the following ion involved in the above process will show paramagnetism?

(A) V5+ (B) V4+ (C) O2– (D) 3VO

Tr ue / Fa l se

1. T 2. F 3. F 4. T 5. T 6. F

Fi l l i n the B lanks

1. Mn+2 2. FeSO4.7H

2O, ZnSO

4.7H

2O 3. CuCl

2 4. Cr

2O

7–2 5. Sc+3

Match the Co lumn

1. (A) r,s; (B) r,s ; (C) p,q ; (D) p 2. (A) r ; (B) s ; (C) p ; (D) q

Asser t i on - Reason Ques t ions

1.C 2.B 3 .D 4. C 5. C 6 .B 7.B 8.C 8.B

Comprehens ion Based Ques t ions

Comprehension #1 : 1. B 2. B 3. C 4. B

Comprehension #2 : 1. C 2. D 3. A 4. B

MISCELLANEOUS TYPE QUESTION EXERCISE -3ANSWER KEY

1 . What happens when excess of ammonia is added to CuSO4 solution ?

2 . Why does AgCl dissolve in ammonia solution ?

3 . Why is that orange solution of K2Cr

2O

7 turns yellow on adding NaOH to it ?

4 . Name one ore of manganese and chromium.

5 . The electronic configuration of Co2+ and Cu2+ is d7 and d9 resepctively, which of these ions is expecteed to be

more paramagnetic ?

6 . Write the highest oxidation state shown by element with atomic number 23

7 . One unpaired electron in atom contributes a magnetic moment of 1.1 BM. Calculate the magnetic moment

of Cr (At. No. 24)

8 . Why first ionisation energy of Cu is higher than that of sodium ?

9 . Which is more stable Fe2+ or Fe3+ and why ?

1 0 . Why is KMnO4 kept in dark bottles ?

1 1 . What is Baeyer's reagent ?

1 2 . Account for the following that enthalpies of atomisation of transition elements are quite high.

1 3 . Which d-block element is not normally considered as transition elements ?

1 4 . Transition metals are weak reducing agents. Why?

1 5 . Zinc but not copper is used for the recovery of silver from the complex [Ag(CN)2]. Why?

1 6 . Explain : Blue colour of CuSO4 solution is discharged slowly when an iron rod is dipped into it.

1 7 . Explain : Green solution of potassium manganate (VI) K2MnO

4 turns purple and a brown solid is precipitated

when CO2 is bubbled into the solution.

1 8 . Explain : When Mn(OH)2 is made by adding an alkali to a solution containing Mn2+ ions, the ppt quickly

darkens, and eventully goes black.

1 9 . Explain : A deep blue colour is produced when Fe2+ reacts with K3[Fe(CN)

6]

2 0 . Explain : The colour of mercurous chloride changes from white to black when treated with ammonia solution.

EXERCISE–04 [A] CONCEPTUAL SUBJECTIVE EXERCISE

1 . [Cu(NH3)4]SO

4

2 . Complex formation [Ag(NH3)2]Cl

4 . Pyrolusite = MnO2

Chromite = FeO.Cr2O

3

Fe(CrO2)2

FeCr2O

4

5 . Co+2 = more paramagnetic

d7 = n = 3 Cu+2 = d9 = n = 1

6 . + 5

7 . Cr = 3d5 4s1

n = 6

= 6.6

8 . Small size and maximum zeff of Cu than Na

9 . Fe+3 > Fe+2

3d5 3d6

Half filled Incomplete

1 0 . KMnO4 is photosensative.

1 2 . Strong metallic bond strength.

1 3 . IIB or 12 or volatile metal (Zn, Cd, Hg)

1 4 . Due to high heat of sublimation, high ionisation energy and low E0R.P.

1 5 . Zinc is cheaper as well as strong reducing agent than Cu and replaces Ag from complex.

1 6 . Iron is above copper in electrochemical series.

1 7 . CO2 in aqueous solution gives bicarbonate and is acidic.

CO2 + H

2O H

2CO

3 H+ + HCO3

(purple by oxidation) and MnO2 (brown solid, by reduction)

1 8 . The black colour is due to the manganese (VI) oxide MnO2. It is made by the Mn(OH)

2 being oxidized by

oxygen in air

1 9 . FeIISO4 + K

3[FeIII(CN)

6] KFeII[FeIII(CN)

6 ]

Turn bull's blue (deep blue colour)

2 0 . Hg2Cl

2 absorbs NH

3 to form a mixture of mercury and mercuric qminochloride, black substance.

Hg2Cl

2 + 2NH

4OH Hg

NH2

Clblack

+ Hg + NH4Cl + 2H

2O

CONCEPTUAL SUBJECTIVE EXERCISE EXERCISE -4 (A)ANSWER KEY

1 . What happens when silver sulphide is shaken with NaCN solution ?

2 . Give the formula of the complex used in electroplating of object by silver.

3 . What is the coordination entity formed when excess of aqueous KCN is added to an aqueus solution of

copper sulphate? Why is it that no precipitate of copper sulphide is obtained when H2S(g) is passed through

this solution?

4 . Why are the compounds of transition metal generally coloured ?

5 . Why HCI not used to acidify a KMnO4 solutions in volumetric estimations of Fe2+ or 2 -

2 4C O ?

6 . Why is K2Cr

2O

7 generally preferred over Na

2Cr

2O

7 in volumetric analysis although both are oxidising agents ?

7 . K2PtCl

6 is well known compound whereas corresponding Ni compound is not known .

Explain

8 . Complete the following :

TiCl4 + H

2O

9 . What is the percentage of gold in 22 carat gold ?

1 0 . Why do the transition metals exhibit higher enthalpies of atomisation ?

1 1 . (a) Of the ions Ag+, Co2+, Ti4+, which one will be coloured in aqueous solutions.

[Atomic no : Ag = 47, Co = 27, Ti = 22]

(b) If each one of the above ionic species is in turn kept in a magnetic field, how will it respond and why ?

1 2 . Write balanced equations for the reaction between K2Cr

2O

7 and acidified solution :

(i) Ferrous sulphate

(ii) KI solution.

1 3 . Describe the preparation of potassium permanganate. How does the acidified permanganate solution re-

acts with

(a) iron (II) ions

(b) SO2

(c) oxalic acid ?

Write the ionic equation for the reactions.

1 4 . What happens when aqueous ammonia reacts with :

(a) Silver chloride (b) Mercury (I) chloride (c) Mercury (II) chlroride ?

1 5 . What are the equivalent weights of oxalic acid and potassium permaganate in their titration in acidic medium?

(K=39, Mn=55)

1 6 . Complete the following chemical equations :

(i) MnO2

+ KOH+O2

Heat

(ii) Cr2O7

2 +H2S + H+

(iii) I– +2Mn O4

+H2O MnO

2 +2OH– + IO

3–1

1 7 . When H2S is passed into FeCl

3 solution yellow colour of FeCl

3 changes to light green ? Explain.

EXERCISE–04 [B] BRAIN STORMING SUBJECTIVE EXERCISE

1 8 . Identify (A) to (F) in the followig:

FeSO4 (A)

(B) + (C) + (D)

(C) and (D) are gases, (B) is red-brown solid, (C) can be oxidised to (D). (C) also turns 22 7Cr O /H

+ solution

green. (B) dissolves in HCl forming deep yellow solution (E). (E) gives blue colour (F) with K4[Fe(CN)

6]. (D)

dissolves in H2O forming a well knows mineral acid called "king of acids".

1 9 . 2.78 g of FeSO4 . xH

2O is treated with excess of BaCl

2 then 2.33 g of white precipitate are obtained.

Calculate the value of x. (Ba = 137, S = 32, Fe = 56, H = 1, O = 16).

2 0 . Suggest a series of reactions, using common chemicals, by which each of the following synthesis can be

performed:

(a) Fe(OH)3 from FeS

(b) BaCrO4 from BaCO

3 and K

2Cr

2O

7

(c) CrCl3 from (NH

4)2Cr

2O

7

(d) MnCO3 from MnO

2

2 1 . A white amorphous powder (A) on heating yields a colourless, non combustible gas (B) and a solid (C).

The later compound assumes a yellow colour on heating and changes to white on cooling. (C) dissolves

in dilute acid and the resulting solution gives a white ppt. on adding K4[Fe(CN)

6] solution. (A) dissolves in

dilute HCl with evolution of gas, which is identical in all respect to (B). The gas (B) turns lime water milky,

but the milkiness disappears with the continuous passage of gas. The solution of (A) as obtained above

gives a white precipitate (D) on the addition of excess NH4OH and passing H

2S. Another portion of the

solution initially gives a white precipitate (E) on the addition of NaOH solution, but dissolves on further

addition of the base. Identify (A) to (E).

2 2 . A compound (A) is greenish crystalliner salt which gave the following results:

(i) Adition of BaCl2 solution to solution of (A) results in the formation of a white ppt. (B), which is insoluble

in dil. HCl.

(ii) On heating (A), water vapours and two oxides of sulphur, (C) and (D) are liberated leaving a red brown

residue (E).

(iii) (E) dissolves in warm conc. HCl to give a yellow solution (F).

(iv) With H2S, the solution (F) yields a pale yellow ppt. (G), which when filtered, leaves a greenish filtrate (H).

(v) Solution (F) on treatment with thiocyanate ions gives blood red coloured compound (I).

Identify the substances from (A) to (I)

1 . Ag2S + 4NaCN 2Na[Ag(CN)

2] + Na

2S

2 . Na[Ag(CN)2]

3 . CuSO4 + KCN Cu(CN)

2

2Cu(CN)2 2CuCN + NC–CN (Cyanogen)

CuCN + KCN K3[Cu(CN)

4]

K3[Cu(CN)

4] 3K+ [Cu(CN)

4]–3 H S2 no ppt

4 . Due to presence of unpaired electron and d-d transition

5 . KMnO4 oxidizes HCl to Cl

2

6 . Na2Cr

2O

7 is deliquescent in nature

7 . Pt+4 is thermo dynamically more stable than Ni+4.

8 . TiCl4 + H

2O Ti(OH)

4 + 4HCl

1 0 . Due to strong metallic bond strength

1 1 . (a) Ag+ = 5d10 n = 0

Ti+4 = 3s2 3p6 n = 0

Co+2 = [Ar] 3d7 n = 3

(b) Co+2 attracted by a magnetic field due to presence of unpaired electron.

1 2 . (i) Cr2O

7–2 + 6Fe+2 14H 2Cr+3 + 6Fe+3

+ 7H2O

(ii) Cr2O

7–2 + 6I– + 14H+ 2Cr+3 + 3I

2

+ 7H2O

1 3 . (a) 2MnO4

– + 16H + 10Fe+2

2Mn+2 + 8H2O + 10 Fe+3

(b) 2MnO4

– + 5SO2 + 2H

2O

5SO4

–2 + 2Mn+2 + 4H

(c) 2MnO4

– + 16H +5C2O

4–2

2Mn+2 + 8H2O + 10CO

2

1 4 . (a) AgCl + 2NH4OH [Ag(NH

3)2] +2H

2O

(b) Hg2Cl

2 + NH

3 Hg + HgNH

2Cl+NH

4Cl

(c) HgCl2 + 2NH

3aq. Hg(NH

2)Cl + NH

4Cl

Mercury aminochlordie

1 5 . In acidic medium

Equivalent weight of oxalic acid = 90

2= 45

CONCEPTUAL SUBJECTIVE EXERCISE EXERCISE -4 (B)ANSWER KEY

Equivalent weight of KMnO4

=158

5= 31.6

1 6 . (i) MnO2

+ KOH+O2

2K2

MnO4

+ 4H2O

pot manganate

(ii) Cr2O7

2 +3H2S + 8H+ 2Cr3+ 7H

2O +3S

(iii) 2Mn O4 +I– + H

2O 2MnO

2 +2OH– + IO3

1

1 7 . Solution changes to light green due to reduction of Fe3+ to Fe2+

FeCl3

+ H2S 2FeCl

2 +2HCl + S

1 8 . (A) : FeSO4 (B) : Fe

2O

3 (C) : SO

2 (D) : SO

3 (E) : FeCl

3 (F) : KFeIII [FeII(CN)

6, Prussian blue.

1 9 . x = 7

2 0 . (a) FeS H SO2 4

FeSO HS4 2

NaOH + HO2 2

Fe(OH)3

(b) BaCO BaCl3 2HCl

KOH

CO2

BaCrO4

(c)

HO, N2 2

Conc. HCl

CrCl3

(d),conc. HCl

Cl2

NaCO2 3

MnCO3

2 1 . (A) : ZnCO3 (B) : CO

2 (C) : ZnO (D) : Zn(OH)

2 (E) : Na

2ZnO

2

2 2 . (A) : FeSO4 · 7H

2O (B) : BaSO

4 (C) : SO

2 (D) : SO

3 (E) : Fe

2O

3 (F) : FeCl

3 (G) : S

(H) : FeCl

2 (I) : Fe(CNS)

3

EXERCISE–05 [A] PREVIOUS YEARS QUESTIONS

1 . The radius of La3+ is 1.06Å, which of the following given values will be closest to the radius of Lu3+

(At no. of Lu = 71, La = 57)- [AIEEE-2003]

(1) 1.6 Å (2) 1.4 Å

(3) 1.06 Å (4) 0.85 Å

2 . What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid -

(1) Cr3+ and Cr22 –7O are formed [AIEEE-2003]

(2) Cr22 –7O and H2O are formed

(3) Cr22 –7O is reduced to +3 state of Cr

(4) Cr22 –7O is oxidised to +7 state of Cr

3 . Cerium (Z = 58) is an important member of the lanthanoids. Which of the following statements about cerium

is incorrect - [AIEEE-2004]

(1) Cerium (IV) acts as an oxidising agent

(2) The +3 oxidation state of cerium is more stable than the +4 oxidation state

(3) The +4 oxidation state of cerium is not known in solutions

(4) The common oxidation states of cerium are +3 and +4

4 . Excess of KI reacts with CuSO4 solution and then Na2S2O3 solution is added to it. Which of the statements is

incorrect for this reaction : [AIEEE-2004]

(1) Evolved I2 is reduced (2) CuI2 is formed

(3) Na2S2O3 is oxidised (4) Cu2I2 is formed

5 . Calomel on reaction with NH4OH gives [AIEEE-2004]

(1) HgNH2Cl (2) NH2–Hg–Hg–Cl

(3) Hg2O (4) HgO

6 . The lanthanoid contraction is responsible for the fact that - [AIEEE-2005]

(1) Zr and Y have about the same radius

(2) Zr and Nb have similar oxidation state

(3) Zr and Hf have about the same radius

(4) Zr and Zn have similar oxidation state

7 . Lanthanoid contraction is caused due to [AIEEE-2006]

(1) the same effective nuclear charge from Ce to Lu

(2) the imperfect shielding on outer electrons by 4f electrons from the nuclear charge

(3) the appreciable shielding on outer electrons by 4f electrons from the nuclear charge

(4) the appreciable shielding on outer electrons by 5d electrons from the nuclear charge

8 . Identify the incorrect statement among the following- [AIEEE-2007]

(1) d-block elements show irregular and erratic chemical properties among themselves

(2) La and Lu have partially filled d-orbitals and no other partially filled orbitals

(3) The chemistry of various lanthanoids is very similar

(4) 4f and 5f-orbitals are equally shielded

9 . The actinoids exhibits more number of oxidation states in general than the lanthanoids. This is because -

(1) The 5f-orbitals are more buried than the 4f-orbitals [AIEEE-2007]

(2) There is a similarly between 4f-and-5f in the their angular part of the wave function

(3) The actinoids are more reactive than the lanthanoids

(4) The 5f-orbitals extend further from the nucleus than the 4f-orbitals

1 0 . Larger number of oxidation states are exhibited by the actinides than those by the lanthanides, the main reason

being [AIEEE-2008]

(1) 4f orbitals more diffused than the 5f orbitals

(2) lesser energy difference between 5f and 6d than between 4f and 5d orbitals

(3) more energy difference between 5f and 6d than between 4f and 5d orbitals

(4) more reactive nature of the actinides than the lanthanides

REMARK : Q. 1, 3, 6, 7, 8, 9 10, 12, 13 (THESE ARE F-BLOCK)

1 1 . In context with the transition elements, which of the following statements is incorrect ? [AIEEE-2009]

(1) In the highest oxidation states of the first five transition elements (Sc to Mn), all the 4s and 3d electrons are

used for bonding.

(2) Once the d5 configuration is exceeded, the tendency to involve all the 3d electrons in bonding decreases.

(3) In addition to the normal oxidation states, the zero oxidation state is also shown by these elements in complexes.

(4) In the highest oxidation states, the transition metal show basic character and form cationic complexes.

1 2 . Knowing that the chemistry of lanthanoids (Ln) is dominated by its +3 oxidation state, which of the following

statements is incorrect ? [AIEEE-2009]

(1) Ln(III) compounds are generally colourless

(2) Ln(III) hydroxides are mainly basic in character

(3) Because of the large size of the Ln(III) ions the bonding in its compounds is predominently ionic in character

(4) The ionic sizes of Ln(III) decrease in general with increasing atomic number

1 3 . In context of the lanthanoids, which of the following statements is not correct ? [AIEEE-2011]

(1) Because of similar properties the separation of langhanoids is not easy

(2) Availability of 4f electrons results in the formation of compounds in +4 state for all the members of the

series

(3) There is a gradual decrease in the radii of the members with increasing atomic number in the series

(4) All the members exhibit +3 oxidation state

1 4 . Iron exhibits +2 and +3 oxidation states. Which of the following statements about iron is incorrect ?

[A IEE E -2012 ]

(1) Ferrous compounds are more easily hydrolysed than the corresponding ferric compounds.

(2) Ferrous oxide is more basic in nature than the ferric oxide.

(3) Ferrous compounds are relatively more ionic than the corresponding ferric compounds.

(4) Ferrous compounds are less volatile than the corresponding ferric compounds.

1 5 . Which of the following arrangements does not represent the correct order of the property stated against it ?

(1) V2+ < Cr2+ < Mn2+ < Fe2+ : paramagnetic behaviour [JEE MAINS-2013]

(2) Ni2+ < Co2+ < Fe2+ < Mn2+ : ionic size

(3) Co3+ < Fe3+ < Cr3+ < Sc3+ : stability in aqueous solution

(4) Sc < Ti < Cr < Mn : number of oxidation states

1 6 . Four successive members of the first row transition elements are listed below with atomic numbers. Which one

of them is expected to have the highest 3 2

0

M /ME

value ? [JEE MAINS-2013]

(1) Cr(Z = 24) (2) Mn(Z = 25)

(3) Fe (Z = 26) (4) Co(Z = 27)

1 7 . Expermentally it was found that a metal oxide has formula M0.98O. Metal M, is present as M2+ and M3+ in its

oxide. Fraction of the metal which exists as M3+ would be :- [JEE MAINS-2013]

(1) 7.01% (2) 4.08%

(3) 6.05% (4) 5.08

PREVIOUS YEARS QUESTIONS EXERCISE -5 [A]ANSWER KEY

Que. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Ans 4 2 3 2 1 3 2 4 4 2 4 1 2 1 1 4 2

1 . Anhydrous ferric chloride is prepared by – [I IT 2002]

(A) Heating hydrated ferric chloride at a high temperature in a steam of air

(B) Heating metallic iron in a steam of dry chlorine gas

(C) Reaction of ferric oxide with HCl

(D) Reaction of metallic iron with HCl

2 . When MnO2 is fused with KOH and KNO

2, a coloured compound is formed, the product and its colour is –

[I IT 2003]

(A) K2MnO

4, green (B) KMnO

4, purple (C) Mn

2O

3, brown (D) Mn

3O

4, black

3 . (NH4)2Cr

2O

7 on heating gives a gas, which is also given by – [IIT- 2004]

(A) Heating NH4NO

2(B) Heating NH

4NO

3(C) Mg

3N

2 + H

2O (D) Na + H

2O

2

4 . The pair of compounds having metals in their highest oxidation state is – [ I IT -2004]

(A) MnO2, FeCl3 (B) [MnO4]–, CrO2Cl2 (C) [Fe(CN)6]3–, [Co(CN)3] (D) [NiCl4]2–, [CoCl4]–

5 . The compound having tetrahedral geometry is – [I IT- 2004]

(A) [Ni(CN)4]2– (B) [Pd(CN)4]2– (C) [PdCl4]2– (D) [NiCl4]2–

6 . Spin only magnetic moment of the compound Hg[Co(SCN)4] is – [I IT- 2004]

(A) 3 (B) 15 (C) 24 (D) 8

7 . Which pair of compounds is expected to show similar colour in aqueous medium? [IIT- 2004]

(A) FeCl3 and CuCl2 (B) VOCl2 and CuCl2 (C) VOCl2 and FeCl2 (D) FeCl2 and MnCl2

8 . NiCl2 in the presence of dimethyl glyoxime (DMG) gives a complex which precipitates in the presence of

NH4OH, giving a bright red colour. [ I IT- 2004]

(a) Draw its structure and show H-bonding

(b) Give oxidation state of Ni and its hybridisation

(c) Predict whether it is paramagnetic or diamagnetic.

9 . A solution of a metal ion when treated with KI gives a red precipitate which dissolves in excess KI to give a

colourless solution. Moreover, the solution of metal ion on treatment with a solution of cobalt(II) thiocyanate

gives rise to a deep blue crystalline precipitate. The metal ion is – [I IT- 2005]

(A) Pb2+ (B) Hg2+ (C) Cu2+ (D) Co2+

1 0 . Write balanced chemical equation for developing a black and white photographic film. Also give reason why

the solution of sodium thiosulphate on acidification turns milky white and give balance equation of this

reaction – [I IT- 2005]

1 1 . Fe3+ –SNC (excess)

A –F (excess)

B [IIT- 2005]

Blood red Colourless

Identify A and B.

(i) Write IUPAC name of A and B.

(ii) Find out spin only magnetic moment of B

1 2 . Consider a titration of potassium dichromate solution with acidified Mohr's salt solution using diphenylamine

as indicator. The number of moles of Mohr's salt required per mole of dichromate is – [I IT- 2007]

(A) 3 (B) 4 (C) 5 (D) 6

EXERCISE–05 [B] PREVIOUS YEARS QUESTIONS

1 3 . Match the column [IIT- 2007]

Co lumn- I Co lumn- I I

(A) –2O O2 + 2–

2O (p) redox reaction

(B) 2–4

CrO + H+ (q) one of the products has trigonal planar structure

(C) –4MnO + –

2NO + H+ (r) dimeric bridged tetrahedral metal ion

(D) –3NO + H2SO4 + Fe

2+ (s) disproportionation

1 4 . Upon treatment with ammonical H2S , the metal ion that precipitates as a sulphide is - [ I IT -2013]

(A) Fe(III) (B) Al(III)

(C) Mg(II) (D) Zn (II)

PREVIOUS YEARS QUESTIONS EXERCISE -5 [B]

1. B 2. A 3. A 4. B 5. D 6. B 7. B

8 . (a) Structure of the complex is

HC–C=N3

HC–C=N3

N = C–CH3

N = C–CH3

O............. H—O–

O—H ............ O–

Ni

Hydrogen bonding

Hydrogen bonding

(b) The oxidation state of Ni in this compouind is +2 and it shows dsp2 hybridisation.

(c) Since the coordination number of Ni in this complex is 4. According to crystal field theory it is diamagnetic in nature

9. (B)

1 0 . (i) The following reactions are used in developing the photographic film.

2AgBr +

OH

OH

Hydroquinone (developer)

2Ag + 2HBr +

O

O

Quinone

AgBr + 2Na2S

2O

3 Na

3[Ag(S

2O

3)2] + NaBr

hypo solution soluble

(ii) Aqueous solution of sodium thiosulphate (Na2S

2O

3) on acidification gives milky white turbidity of collodial

sulphur. Na2S

2O

3 + (aq ).2H 2Na+ + H

2SO

3 + S (colloidal sulphur)

1 1 . (a) A : [Fe(SCN)(H2O)

5]2+ (Pentaaquathiocyanatoferrate(III)ion) B : [FeF

6]3– (Hexafluoroferrate(III) ion)

(b) 5.92 BM

12. D 13. (A) p,s ; (B) r ; (C) p,q ; (D) p 14. (D)

ANSWER KEY