1293 + Interview Questions in D-AND-F-BLOCK-ELEMENTS IN GENERAL AWARENESS Page 14 InterviewSolution

651.	Important ore of iron isA. GarnieriteB. PentalanditeC. HaematiteD. Smaltite
Answer» Correct Answer - c Haematite `(Fe_2O_3)` is an ore of iron. Garnierite is hydrated double silicate of Mg and Si having `5-8%` Ni.

Discussion

652.	Which of the following oxides of Cr is amphoteric.A. `CrO_2`B. `Cr_2O_3`C. `CrO_5`D. `CrO_3`
Answer» Correct Answer - a Acidic nature of oxides increases with the increase in O.S. Of the metal atom e.g. `Cr_2O_3` is basic. `CrO_2` is acidic `CrO_5` is also acidic in nature.

Discussion

653.	When `(NH_4)_2CrO_2O_7` is heated, the gas evolved isA. `N_2`B. `NO_2`C. `O_2`D. `Na_2O`
Answer» Correct Answer - a Due to the formation of `Cr^(3+)` from `Cr_2O_7^(2-)` and the solution turns green.

Discussion

654.	Blister copper is `98%` copper.
Answer» Correct Answer - True.

Discussion

655.	Which of the following d-block elements has `d^(10)` configuration ?A. `Cu, Ag, An`B. `Zn, Cd, Hg`C. `Fe, Co, Ni`D. `Ru, Rh, Pd`
Answer» Correct Answer - B

Discussion

656.	The transition elements are so named becauseA. they shows reducing propertyB. their properties are similar to other elementsC. their properties are different from other elementsD. they have party filled d-orbitals
Answer» Correct Answer - D

Discussion

657.	Which one of the following elements exhibits highest valency ?A. MnB. OsC. WD. Mo
Answer» Correct Answer - B

Discussion

658.	The atomic radii of transition series elementsA. increas as thatomic number increases.B. decrease as atomic number increases.C. remains almost constant.D. increase as atomic mass decreases.
Answer» Correct Answer - B

Discussion

659.	Why does Mn(III) undergo disproportionation reaction easily ?
Answer» Mn(III) is highly unstable as it is clear from its very `E_(Mn^(3+)//Mn^(2+))^(@)` value (+1.57 V). As such, it undergoes disproportionation reaction as follows: `2Mn^(3+)(aq) to Mn^(2+)(aq)+Mn^(4+)(aq)`

Discussion

660.	The stability of ferric ion is due toA. Half- filled f-orbitalsB. half-filled d-orbitalsC. completely filled f-orbitalsD. completely filled d-orbitals
Answer» Correct Answer - B `Fe^(3+)` ion has the following configuration . `Fe^(3+)=1s^(2),2s^(2),2p^(6),3s^(2),3p^(6)3d^(5)` Thus, ferric ion is quite stable due to half-filled d-orbital `(3d^(5))`.

Discussion

661.	The stability of ferric ionis due toA. half-filled d-orbitalsB. half-filled f-orbitalsC. compltetly filled d-orbitalsD. completely filledf-orbitals
Answer» `Fe(Z= 26) = 3d^(6)4s^(2)` `:. Fe^(3+) = 3d^(5)` . Thus`,Fe^(3+)` ion is quite stabledue to half-filled d-orbitals.

Discussion

662.	Which one of the following ions is the most stable in aqueous solutions ? (At. No. `Ti=22, V=23, Cr= 24 , Mn = 25)A. `Mn^(2+)`B. ` Cr^(3+)`C. `V^(3+)`D. `Ti^(3+)`
Answer» Out of the given species, `Cr^(3+)` has the highest negative reduction potential.Hence, it cannot be reduced to `Cr^(2+)` and, therefore, is the most stable ion in aqueous solution. Alternatively, `Mn^(3+) = [ AAr] 3d^(4) , Cr^(3+)= [Ar]3d^(3)` `V^(3+) =[Ar]3d^(2)Ti ^(3+) = [ Ar] 3d^(1)` In `Cr^(3+)`, all three d electrons enter into lower energy `t_(2g)` orbitals. The lowering of energy is maximum and hence stability is maximum.

Discussion

663.	The common oxidation state of transition elements isA. `+2`B. `+4`C. `+3`D. `+7`
Answer» Correct Answer - A

Discussion

664.	(a). Explain why `Mn^(3+)` is less stable than `Mn^(22+)` and `M^(4+)` ions? (b). Standard reduction potential of copper is greatr than that of hydrogen yet is librates hydrogen from a concentrated solution of hydrochloric acid. Explain this fact with proper reasoning. `Cu^(2+)+2etoCu_(s)` `E_((Cu^(2+))/(Cu))^(ɵ)=0.34"volt"` `2H^(o+)+2etoH_(2(g))` `E_((H^(o+))/(H_2))=0.00"volt"` (c). An aqueous solution of `FeCl_3` is slightly yellowish in colour. (d). `Cu(I)` compounds are not known in aqueous solution.
Answer» (a). `Mnto3d^5,4s^2`, `Mn^(3+)to3d^4,4s^(0)` `Mn^(2+)to3d^5,4s^0`,`Mn^(4+)to3d^3,4s^0` On the basis of electron configuration `Mn^(2+)` and `Mn^(4+)` are expected to be more stable, hence `Mn^(3+)` undregoes disproportionation. `2Mn^(3+)toMn^(2+)+(mn^(4+)` (b). When copper is treated with conc.HCl then formation of stable complex ion `[CuCl_4]^(2-)` along with liberation of `H_2` gas takes place. `Cu+4HCl_((conc.))to[CuCl_4]^(2-)+2H^(o+)+H_2uarr]` (c). An equeous solution of `FeCl_3` is colloidal. It is yellowish in colour due to Tyndall Effect. (d). `Cu(I)` compounds undergo disproportionation in aqueous medium. `Cu_2Cl_2toCuCl_2+Cu`

Discussion

665.	The most stable oxidation state of copper isA. `+1`B. `+2`C. `+3`D. `+4`
Answer» Correct Answer - A

Discussion

666.	Transitions elements show generally positive oxidation state due toA. large atomic sizeB. low inization energyC. low electronegativityD. high electronegativity
Answer» Correct Answer - C

Discussion

667.	Which element does not show variable oxidation state ?A. ScB. VC. FeD. Hg
Answer» Correct Answer - a

Discussion

668.	which forms interstitial compounds?A. FeB. CoC. NiD. All
Answer» Correct Answer - D All transition metals form interstitial compounds

Discussion

669.	The pair of elements which can show +1 odidation state.A. `Cr, Zn`B. `Fe, Zn `C. `Cr, Cu`D. `Cu, Zn`
Answer» Correct Answer - C

Discussion

670.	Formation of interstitial compound makes the transition metalA. more softB. more ductileC. more metallicD. more hard
Answer» Correct Answer - D Vacant spaces in the lattice are occupied by smaller atoms, that gives hardness.

Discussion

671.	Variable oxidation state is shown byA. normal elementsB. metallic elementsC. nonmetallic elementsD. transition elements.
Answer» Correct Answer - D

Discussion

672.	Anhydrous ferric chloride is prepared byA. Heating hydrated ferric chloride at a high temperature in a stream of air.B. Heating metallic iron in astream of dry chlorine gasC. Reaction of ferric oxide with HClD. Reaction of metallic iron with HCl
Answer» Correct Answer - B By heating metallic iron in a stream of dry chlorine gas. `2FE+3Cl_2to2FeCl_3`

Discussion

673.	Which of the following is an organometallic compound?A. Lithium methoxideB. Lithium acetateC. Lithium dimethylamideD. methyl lithium
Answer» Correct Answer - D Organometallic compound are those compounds in which metal atom is directly bonded with C atom. Methyl lithium is one such compound.

Discussion

674.	Among the following, identify the species with an atom in `+6` oxidation state.A. `MnO_4^(ɵ)`B. `[Cr(CN)_6]^(3-)`C. `[NiF_6]^(2-)`D. `CrO_2Cl_2`
Answer» Correct Answer - D `MnO_4^(ɵ)implies(Mn=+7)[Cr(CN)_6]^(3-)impliesCr(+3)` `[NiF_6]^(2-)implies(Ni=+2)CrO_2Cl_2implies(Cr=+6)`

Discussion

675.	The reason for the stability of `Gd^(3+)` ion isA. 4f-subshell-half filledB. 4f subshell-completely filledC. Possesses the general electronic configuration of noble gasesD. 4f-subshell empty.
Answer» Correct Answer - a `Gd(Z=64)implies4f^75d^16s^2` `Gd^3=4f^7` `Gd^(3+)` is stable due to the presence of exactly half-filled 4f-subshell.

Discussion

676.	Arrange `(I)Cr^(3+),(II)La^(3+),(III)Pm^(3+)` and `(IV)Yb^(3+)` in increasing order of their ionic radii.A. `IVltIIIltIltII`B. `IltIVltIIIltII`C. `IVltIIIltIIltI`D. `IIIltIIltIltIV`
Answer» Correct Answer - a Ionic radii decrease across lanthanide series due to lanthanide contraction. As all ions are in `+3` O.S. ionic radii will follow the trend of atomic radii. `La^(3+)gtCe^(3+)gtPm^(3+)gtYb^(3+)`

Discussion

677.	Anelement which is highly toxic for plants and animals is-A. AuB. MnC. HgD. Ca
Answer» Correct Answer - C `HgCl_(2)` is dangerous poison, the antidote being white of an egg which is coagulated by the salt in the system and is eliminated by the system with salts absorbed in it, also `Hg` itself is very poisonous.

Discussion

678.	(a) How do you prepare `:` (i) `K_(2)MnO_(4)` from `MnO_(2)` (ii) `Na_(2)Cr_(2)O_(7) ` from `Na_(2)CrO_(4)` ? (b) Account for the following `:` (i) `Mn^(2+)` is more stable than `Fe^(2+)` towards oxidation to `+3` state. (ii) The enthalpy of atomisation is lowest for Zn in 3d series of transition elements. (iii) Actinoid elements show wide range of oxidation states. or (i) Name the elements of 3d transition series which shows maximum number of oxidation states. Why dows it show so ? (ii)Which transition element of 3d series has positive `E_(M^(+)//M)^(@)` value and why ? (iii) Out of `Cr^(3+)` and `Mn^(3+)` which is stronger oxidizing agent and why ? (iv) Name a member of the lanthanoid series which is well known to exhibit `+2`oxidation state. (v) Complete the equation `: ` `MnO_(4)^(-) +8 H^(+) + 5e^(-) rarr`
Answer» (i) Mn, (ii)Cu, (ii) `Mn^(3+)`, `(E_(M^(+)//Mn^(2+))^(@)= + 1.57V)` (iv) `Eu^(2+)` due to exactly half filled `f^(7)` configuration and `Yb^(2+)` due to completely filled `f^(14)` configuration (v) `MnO_(4)^(-) +8 H^(+)+ 5e^(-) rarr Mn^(2+) 4H_(2)O)`

Discussion

679.	Give balance chemical equation for the following : (i) Silverf nitrate is added to dilute sodium thiosulphate solution. (ii) Potassium dichromate is treated with acidified ferrous sulphate solution.
Answer» (i) `2AgNO_(3)+Na_(2)S_(2)O_(3) to Ag_(2)S_(2)O_(3) +2NaNO_(3)` (ii) `K_(2)Cr_(2)O_(7)+7H_(2)SO_(4) +6FeSO_(4) to K_(2)SO_(4)+Cr_(2)(SO_(4))_(3)+3Fe_(2)(SO_(4))_(3)+7H_(2)O`

Discussion

680.	When sulphur dioxide gas is passed throught acidified potassium dichromate solution, the colour of the solution changes from:A. orange to blueB. orange to greenC. green to orangeD. orange to colourless
Answer» Correct Answer - B `K_2Cr_2 O_7 + 4H_2SO_4 to K_2SO_4 + underset"Green"(Cr_2(SO_4)_3) + 4H_2O + 3[O]` `SO_2 + [O] + H_2O to H_2SO_4`

Discussion

681.	In context of the lanthanoids, which of the following statements is not correct?A. There is gradual decrease in the radii of the members with increasing atomic number in the seriesB. All the members exhibit +3 oxidation stateC. Because of similar properties the separation of lanthanoids in not easyD. Availability of 4f electrons results in the formation of compounds in +4 state for all members of the series
Answer» Correct Answer - D

Discussion

682.	In context of the lanthanoids, which of the following statements is not correct?A. There is a gradual decrease in the radii of the members with increasing atomic number in the seriesB. All the members exhibit + 3 oxidation stateC. Because of similar properties, the separation of lanthanoids is not easyD. Availability of 4f electrons results in the formation of compounds in + 4 state for all the members of the series
Answer» Correct Answer - D Formation of + 4 state requires very high energy, thus incorrect.

Discussion

683.	Which of the following is radioactive element among the 4-f series ?A. CeB. PmC. HoD. Yb
Answer» Correct Answer - B All lanthanide mineral contains all elements except Pm. Which is radioactive

Discussion

684.	Actinum isA. f-block elementB. d-block elementC. p-block elementD. s-block element
Answer» Correct Answer - B Actinium is d-block element because its has electronic configuration `7s ^(2) , 5f^(0), 6d^(1).`

Discussion

685.	Actinum is the element ofA. transition seriesB. inner transition seriesC. 5f seriesD. none of these
Answer» Correct Answer - A We know that, actinium has electronic configuration `7s^(2), 5f^(0), 6d^(1).` No electrons in 5f orbital. Hence it is niot f-block element. It is d-block or transition element.

Discussion

686.	The total number of rare earth elements isA. 8B. 32C. 14D. 10
Answer» Correct Answer - C 4f series elements also known as rare earth, are 14.

Discussion

687.	Which of the following can exhibit +4 oxidation state?A. LaB. CeC. EuD. Gd
Answer» Correct Answer - B Ce can exhibit +4 oxidation state. Electronic configuration of Ce is `[Xe]4f^2 5d^0 6s^0 ` . It loses 2 electrons from 4f and 2 electrons from 6s orbitals and gives stable electronic configuration for `Ce^(+4)` ion `[Xe] 4f^0 5d^0 6s^2`

Discussion

688.	Why in any transition series, melting points first increase and then decrease and also they show a dip in the middle?
Answer» Milting points first increase because the number of unpaired electrons increases and hence strength of metallic bond increases. After reaching the maximum, the melting points decrease because the pairing of electrons starts in the d-subshell and number of unpaired electrons decreases and so the strength of metallic bond decreases. The dip in the middle is due to exactly half-field configuration of d-subshell which has higher stability. Hence electrons are held tightly by the nucleous .As a result metallic bond is weaker.

Discussion

689.	Why does vanadium pentaoxide act as a catalyst?
Answer» Vanadium exists in multiple oxidation states.

Discussion

690.	Write all possible oxidation states of an element having atomic number 25
Answer» E.C.of `._(25)Mn= [Ar]^(18) 3d^(5) 4s^(2)`. It shows oxidation states of`+2, +3,+4,+5,+6` and `+7`.

Discussion

691.	Why in any transition series, melting points first increase and then decrease and also they sow a dip in the middle ?
Answer» Melting points first increase because the number of unpaired electrons increasesand hence strength of metallic bondincreases. After reaching themaximum, the melting points decrease the pairing of electrons starts in the d-subshell and number of unpaired electrons decreases and so the strength of metallic bond decreases. Thedip in teh middle is due to exactly half-filled configuration of d-subshell which has higher stability . Hence, electrons are held tightly by the nucleus. As a result , metallic bond is weaker.

Discussion

692.	Why hydrated copper sulphate is blue while anhydrous copper sulphate is white ?
Answer» In hydrated copper sulphate , four water molecules are present as ligands. In the presence of these ligands d-orbitals are no longer degenerate in energy. Hence, d-d transition takes place absorbing red wavelength. The complementary colour, viz, blue is reflected . In anhydrous`CuSO_(4)`, d-orbitals remain degenerate.Hence,no d-d transition can occur. The white light is completely reflectedback. Hence, it looks white.

Discussion

693.	A hydrated metallic salt A, light green in colour, gives a white anhydrous residue B after being heated gradually. B is soluble in water and its aqueous solution reacts with NO to give a dark brown compound C. B on strong heating gives a brown resiodue D and a mixture of two gases E and F. The gaseous mixture, when passed through acidified `KMnO_4` discharges the pink colour, when passed through acidified `BaCl_2` solution, gives a white precipitate. Identifty A, B, C, D, E and F
Answer» `FeSO_4.7H_2O(A)overset(triangle)toFeSO_4(B)` (White) `FeSO_4+No overset(H_2O)to[Fe(H_2O)_5NO]SO_4(C)` `FeSO_4overset(triangle)toFe_2SO_3(D)+SO_3(E)+SO_3(F)` `SO_2+SO_3+KMnO_4toMn^(2+)` (pink solution) `SO_2+SO_3+BaCl_2toBaSO_4` (White precipitate)

Discussion

694.	The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.A. `3d^(7)`B. `3d^(5)`C. `3d^(8)`D. `3d^(2)`
Answer» Correct Answer - B (b) The element with `3d^(5)` configuration has maximum unpaired electrons. It shows highest magnetic movement.

Discussion

695.	`MnO_(4)^(2-)` in acidic solution undergoes disportionation to give `"…....................."` and `"…..................."`.
Answer» Correct Answer - `MnO_(4)^(-), MnO_(2)`

Discussion

696.	The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition elements, which shows highest magnetic moment.A. `3d^(7)`B. `3d^(5)`C. `3d^(8)`D. `3d^(2)`
Answer» Correct Answer - b `3d^(5)` has maximum unpaired electrons `( = 5)`.

Discussion

697.	Which of the following reactions are disproportionation reactions ?A. `Cu^(+) rarr Cu^(2+) + Cu`B. `3MnO_(4)^(-) + 4H^(+) rarr 2MnO_(4)^(-) + MnO_(2)+ 2H_(2)O`C. `2KMnO_(4) +rarr K_(2)MnO_(4) + 2H_(2)O`D. `2MnO_(4)^(-) + 3Mn^(2+) + 2H_(2)O rarr 5MnO_(2) + 4H^(+)`
Answer» Correct Answer - a In (i) , `Cu^(+)` is oxidized as well as reduced. In (ii) , `MnO_(4)^(-)` ions are oxidised as well as reduced.

Discussion

698.	When heated strongly , `KMnO_(4)` decomposes to form `"…..................."` and `"….................."`
Answer» Correct Answer - `K_(2)MnO_(3) , O_(2)`

Discussion

699.	Which one of the following reactions involves disproportionation ?A. `2H_(2)SO_(4)+Cu rarrCuSO_(4) + 2H_(2)O + SO_(2)`B. `As_(2)O_(3) + 3H_(2)S rarrAs_(2)S_(3) + 3H_(2)O`C. `2KOH + Cl_(2) rarr KCl + KOCl + H_(2)O`D. `Ca_(3)P_(2) + 6H_(2)O rarr 3Ca(OH)_(2)+ 2PH _(3)`
Answer» A disproportionation reaction is one in which the same substance undergoes oxidation as well as reduction. In (c ) . `overset(0)(Cl_(2))rarrKoverset(-1)(Cl) ` and also `overset(0)(Cl_(2))rarr KOoverset(-1)(Cl)`

Discussion

700.	Prussian blue isA. `K_(3)[Fe(CN)_(6)]`B. `K_(4) [Fe(CN)_(6)]`C. `Kfe[Fe(CN)_(6)]`D. `Fe_(4)[Fe(CN)_(6)]`
Answer» Prussian blue in `K overset(III)(Fe)[overset(II) (Fe) (CN)_(6)]`

Discussion

Explore topic-wise InterviewSolutions in .

Important ore of iron isA. GarnieriteB. PentalanditeC. HaematiteD. Smaltite

Which of the following oxides of Cr is amphoteric.A. `CrO_2`B. `Cr_2O_3`C. `CrO_5`D. `CrO_3`

When `(NH_4)_2CrO_2O_7` is heated, the gas evolved isA. `N_2`B. `NO_2`C. `O_2`D. `Na_2O`

Blister copper is `98%` copper.

Which of the following d-block elements has `d^(10)` configuration ?A. `Cu, Ag, An`B. `Zn, Cd, Hg`C. `Fe, Co, Ni`D. `Ru, Rh, Pd`

The transition elements are so named becauseA. they shows reducing propertyB. their properties are similar to other elementsC. their properties are different from other elementsD. they have party filled d-orbitals

Which one of the following elements exhibits highest valency ?A. MnB. OsC. WD. Mo

The atomic radii of transition series elementsA. increas as thatomic number increases.B. decrease as atomic number increases.C. remains almost constant.D. increase as atomic mass decreases.

Why does Mn(III) undergo disproportionation reaction easily ?

The stability of ferric ion is due toA. Half- filled f-orbitalsB. half-filled d-orbitalsC. completely filled f-orbitalsD. completely filled d-orbitals

The stability of ferric ionis due toA. half-filled d-orbitalsB. half-filled f-orbitalsC. compltetly filled d-orbitalsD. completely filledf-orbitals

Which one of the following ions is the most stable in aqueous solutions ? (At. No. `Ti=22, V=23, Cr= 24 , Mn = 25)A. `Mn^(2+)`B. ` Cr^(3+)`C. `V^(3+)`D. `Ti^(3+)`

The common oxidation state of transition elements isA. `+2`B. `+4`C. `+3`D. `+7`

The most stable oxidation state of copper isA. `+1`B. `+2`C. `+3`D. `+4`

Transitions elements show generally positive oxidation state due toA. large atomic sizeB. low inization energyC. low electronegativityD. high electronegativity

Which element does not show variable oxidation state ?A. ScB. VC. FeD. Hg

which forms interstitial compounds?A. FeB. CoC. NiD. All

The pair of elements which can show +1 odidation state.A. `Cr, Zn`B. `Fe, Zn `C. `Cr, Cu`D. `Cu, Zn`

Formation of interstitial compound makes the transition metalA. more softB. more ductileC. more metallicD. more hard

Variable oxidation state is shown byA. normal elementsB. metallic elementsC. nonmetallic elementsD. transition elements.

Anhydrous ferric chloride is prepared byA. Heating hydrated ferric chloride at a high temperature in a stream of air.B. Heating metallic iron in astream of dry chlorine gasC. Reaction of ferric oxide with HClD. Reaction of metallic iron with HCl

Which of the following is an organometallic compound?A. Lithium methoxideB. Lithium acetateC. Lithium dimethylamideD. methyl lithium

Among the following, identify the species with an atom in `+6` oxidation state.A. `MnO_4^(ɵ)`B. `[Cr(CN)_6]^(3-)`C. `[NiF_6]^(2-)`D. `CrO_2Cl_2`

The reason for the stability of `Gd^(3+)` ion isA. 4f-subshell-half filledB. 4f subshell-completely filledC. Possesses the general electronic configuration of noble gasesD. 4f-subshell empty.

Arrange `(I)Cr^(3+),(II)La^(3+),(III)Pm^(3+)` and `(IV)Yb^(3+)` in increasing order of their ionic radii.A. `IVltIIIltIltII`B. `IltIVltIIIltII`C. `IVltIIIltIIltI`D. `IIIltIIltIltIV`

Anelement which is highly toxic for plants and animals is-A. AuB. MnC. HgD. Ca

Give balance chemical equation for the following : (i) Silverf nitrate is added to dilute sodium thiosulphate solution. (ii) Potassium dichromate is treated with acidified ferrous sulphate solution.

When sulphur dioxide gas is passed throught acidified potassium dichromate solution, the colour of the solution changes from:A. orange to blueB. orange to greenC. green to orangeD. orange to colourless

Which of the following is radioactive element among the 4-f series ?A. CeB. PmC. HoD. Yb

Actinum isA. f-block elementB. d-block elementC. p-block elementD. s-block element

Actinum is the element ofA. transition seriesB. inner transition seriesC. 5f seriesD. none of these

The total number of rare earth elements isA. 8B. 32C. 14D. 10

Which of the following can exhibit +4 oxidation state?A. LaB. CeC. EuD. Gd

Why in any transition series, melting points first increase and then decrease and also they show a dip in the middle?

Why does vanadium pentaoxide act as a catalyst?

Write all possible oxidation states of an element having atomic number 25

Why in any transition series, melting points first increase and then decrease and also they sow a dip in the middle ?

Why hydrated copper sulphate is blue while anhydrous copper sulphate is white ?

The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.A. `3d^(7)`B. `3d^(5)`C. `3d^(8)`D. `3d^(2)`

`MnO_(4)^(2-)` in acidic solution undergoes disportionation to give `"…....................."` and `"…..................."`.

The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition elements, which shows highest magnetic moment.A. `3d^(7)`B. `3d^(5)`C. `3d^(8)`D. `3d^(2)`

Which of the following reactions are disproportionation reactions ?A. `Cu^(+) rarr Cu^(2+) + Cu`B. `3MnO_(4)^(-) + 4H^(+) rarr 2MnO_(4)^(-) + MnO_(2)+ 2H_(2)O`C. `2KMnO_(4) +rarr K_(2)MnO_(4) + 2H_(2)O`D. `2MnO_(4)^(-) + 3Mn^(2+) + 2H_(2)O rarr 5MnO_(2) + 4H^(+)`

When heated strongly , `KMnO_(4)` decomposes to form `"…..................."` and `"….................."`

Which one of the following reactions involves disproportionation ?A. `2H_(2)SO_(4)+Cu rarrCuSO_(4) + 2H_(2)O + SO_(2)`B. `As_(2)O_(3) + 3H_(2)S rarrAs_(2)S_(3) + 3H_(2)O`C. `2KOH + Cl_(2) rarr KCl + KOCl + H_(2)O`D. `Ca_(3)P_(2) + 6H_(2)O rarr 3Ca(OH)_(2)+ 2PH _(3)`

Prussian blue isA. `K_(3)[Fe(CN)_(6)]`B. `K_(4) [Fe(CN)_(6)]`C. `Kfe[Fe(CN)_(6)]`D. `Fe_(4)[Fe(CN)_(6)]`