94420 + Interview Questions in Chemistry in Class 12

1.	[Fe(CN)_6]^(4-) ion is:
Answer» Octahedral Square planar Bipyramidal Tetrahedron Answer :A

Discussion

2.	[Fe(CN)_(6)]^(4-) and [Fe(H_(2)O)_(8)]^(2+) are of different colours in dilute solutions. Why
Answer» Solution :In both the complexes, `Fe is in +2` state with the configuration `3d^(6)`, i.e., it has FOUR unpaired electrons. As the ligands `H_(2)O and.`CN^(-)` posses, different CRYSTAL FIELD splitting energy(triangle_(o))`, they absorb different components of the visible light (VIBGYOR) for d-d TRANSITION. HENCE, the transmitted colours are different

Discussion

3.	[Fe(CN)_(6)]^(4-) and [Fe(H_(2)O)_(6)]^(2+) are of different colours in dilute solutions. Why ?
Answer» SOLUTION :In both the complexes, Fe is in +2 state with the CONFIGURATION `3d^(6)`, having four unpaired electrons. As the ligands `H_(2)O` and `CN^(-)` POSSESS different crystal field splitting energy (`Delta_(0)`), they absorb different wavelengths of the visible light for d - d transition. HENCE, the transmitted colours are different.

Discussion

4.	[Fe(CN)_(6)]^(4-) and [Fe(CN)_(6)]^(3-) have different _________ but same _________.
Answer» SOLUTION :MAGNETIC MOMENT, STRUCTURE

Discussion

5.	[Fe(CN)_6]^(4-) and Fe(H_2 O)_6]^(2+) are different colours in dilute solutions . Why ?
Answer» Solution :In both the COMPLEXES, Fe is in +2 state with the configuration `3d^6`, i.e., it has FOUR unpaired electrons. In the presence of WEAK `H_2 O` ligand, they do not pair up. In the presence of strong CN ligand, they pair up leaving no unpaired electron. DUE to the difference in the number of unpaired electrons, they have different colours.

Discussion

6.	[Fe(CN)_5NO]^(2-)+S^(2-)toProduct[X] Answer the following questions for the product [X]. (i)Number of negative monodenate ligand(s). (ii)Effective atomic number of iron in the complex. (iii)Number of unpaired electrons
Answer» Solution :(i)five `CN^(-)` and ONE `NOS^(-)`=6 (ii)Iron is in +2 OXIDATION state and atomic number of iron is 26. Therefore, EAN=24+12=36 (iii)`Fe^(2+)=3d^(5)4s^(0)` `CN^-` is strong FIELD ligand which compels for paring of electron. Therefore , there is one unpaired electron.

Discussion

7.	FeCL_(3)+KI to Fe^(2+)(aq.)+KI_(3)
Answer» For COLOURED ppt./Black ppt For coloured solution. for clear/colourless solution For WHITE ppt. Answer :B

Discussion

8.	FeCl_3 on reaction with K_4[Fe(CN)_6] in aq solution gives blue colour and these are separated by a semi permeable membrane Due to osmosis there is
Answer» blue COLOUR FORMATION in the SOLUTION of`FeCl_3` blue colour formation in the solution of`K_4[Fe(CN)_6]` blue colour formation in both the solutions no blue colour formation Answer :D

Discussion

9.	FeCl_(3) on reactiSon with K_(4)[Fe(CN)_(6)] in aq solution gives blue colour of these are separated by a semi permeable memrane AB as shown, Due to osmosis there is
Answer» BLUE colour formation in side X blue colour formation in side Y blue colour formation in both SIDES X & Y no blue colour formation ANSWER :D

Discussion

10.	FeCl_3 solution on reaction with SO_2 changes to:
Answer» `FeCl_2` `Fe_2(SO_4)_3` `Fe_2(SO_3)_3` `FeSO_4` ANSWER :A

Discussion

11.	FeCl_(3) and CoCl_(2) have primary valencies of
Answer» 2 and 2 2 and 1 3 and 2 2 and 3 Answer :C

Discussion

12.	FeCl_(3) is known but not Fel_(3) Why?
Answer» Solution :`I^(-)` is a strong REDUCING agent, it reduces `Fe^(3+)` to `Fe^(2+) (or) Fe^(3+)`can oxidise `I^(-)` to `I_(2)`but not `CL^(-)` to `Cl_(2).2Fe^(3+)+2I^(-)rarr 2Fe^(2+)+I_(2)`. THUS `FeCl_(3)` is KNOWN but not `Fel_(2)`.

Discussion

13.	FeCl_(3) has each of the following characteristics except :
Answer» it exists as dimer its aqueous solution is basic in nature its is used for stopping from a FRESH cut. on heating above 973 K it dissociates to ferrous CHLORIDE and GIVES `Cl_(2)` ANSWER :B

Discussion

14.	FeCl_2 reacts with SO_2
Answer» to GIVE FeS to give FeO Fe will be oxidized Fe will be reduced Answer :C

Discussion

15.	FeC_3 is added separately to excess of boiling water and excess of NaOH solution, the sols obtained contain respectively the disperse particles to be :
Answer» `F_3e_3 C` `F_3e_3^(2) C` `F_3e_3^(3) C I` `F_3 e_3^(3) C I C` Solution :A red SOL of FERRIC hydroxide is OBTAINED by the hydrolysis of ferric chloride with BOILING WATER.

Discussion

16.	FeC_(2)O_(4) can decolorise acidified KMnO_(4) dueto the oxidation of (a) _____and (b)____.
Answer» Answer :a. `Fe^(2+)` B. `C_(2)O_(4)^(2-)`

Discussion

17.	Fear or excitement generally cause one to breathe rapidly and it results in the decreases of concentration of CO_2 in blood. In what way it will change pHof blood :
Answer» PH will increase pH will decrease No change pH will be 7 Answer :C

Discussion

18.	Fe_3O_4 is known ashaematite. True or False
Answer» SOLUTION :MAGNETITE

Discussion

19.	Fe_2O_3 is known as___-.
Answer» SOLUTION :MAGNETITE

Discussion

20.	Fe_3O_4 is known as _____ .
Answer» SOLUTION :MAGNETITE

Discussion

21.	Fe_(3)O_(4) is ferrimagnetic at room temperature but at 850 K it becomes :
Answer» DIAMAGNETIC Ferromagnetic Non-magnetic PARAMAGNETIC ANSWER :D

Discussion

22.	Fe_3O_4 is ferrimagnetic at room temperature but becomes paramagnetic at 850K. Explain.
Answer» Solution :DUE to RANDOMISATION of SPINS at high TEMPERATURE.

Discussion

23.	Fe_(3)O_(4) is:
Answer» FERROMAGNETIC DIAMAGNETIC PARAMAGNETIC FERRIMAGNETIC ANSWER :D

Discussion

24.	Fe_3O_4 has inverse spinel structure. What is not true about this solid ?
Answer» `FE^(3+)` ions are EQUALLY distributed between octahedral and tetrahedral voids Tetrahedral voids are equally distributed between `Fe^(2+)` and `Fe^(3+)` ions No. of `O^(-2) gt Fe^(+3) gt Fe^(+2)` Coordination no. of `Fe^(3+)` =8 through out the unit cell ANSWER :B::D

Discussion

25.	Fe^(3+)overset(SNC^(Θ)("Excess"))rarrunderset("Bloodre"d)(A)overset(F^(ΘExcess))rarrunderset("Colourless")(B) Identify A and B (a) Write the IUPAC name of A and B (b) Find out the spin only magnetic moment of B .
Answer» Solution :`NaS_(2)O_(3)+2HCI rarr 2NaCI +H_(2)O+SO_(2) +S` A is `[Fe(SCN)(H_(2)O)_(5)]^(2+)` The `IUPAC` NAME is pentaaquathiocyanatoferrate(III) ion `B` is `[FeF_(6)]^(3-)` The `IUPAC` mane is hexafluridoferrate(III) `Fe^(3+) + SCNbar rarr [Fe(SCN)(H_(2)O)_(5)]^(2+)` `Fe[SCN(H_(2)O)_(5)]^(2+)+6F rarr [FeF_(6)]^(3-) + SCN^(Θ) +5H_(2)O` `B[FeF_(6)]^(3-)` The oxidation number of ion is + 3 Atomic number = 26 `Fe = [Ar]3d^(6) 4s^(2)` `Fe =[Ar]3d^(5)` Which means five UNPAIRED electrons Spin magnetic moment` sqrt(N(+2))` `=sqrt(5(5+2)) =sqrt35BM` .

Discussion

26.	Fe^(3+)overset(SCN^(-)(excess))to "blood red"(A)overset(F^(-)(excess))to"colourless"(B)Identify A and B (a) Write IUPAC name of A and B (b) Find out spin only magnetic moment of B.
Answer» Solution :`Fe^(3+)unerset(excess)(SCN)^(-)overset(aqueous)tounderset((A)"(blood RED))[Fe(SCN)(H_(2)O)_(5)]]^(2+)``unerset((A)("blood red"))([Fe(SCN)(H_(2)O)_(5)]^(2+)) `unerset(excess)(6F^(-))tounerset((B)("colour LESS")([FeF_(6)]^(3-))+SCN^(-)+5H_(2)O` (a) Pentaaquathiocyanatoiron (III)ion hexafluoroferrate (III) (b) Magnetic moment = SQRT(n(n+2)) = sqrt35 = 5.92 B.M., where n = number of UNPAIRED electrons which is equal to 5 here.

Discussion

27.	Fe^(3+) is reduced to Fe^(2+) by using
Answer» `H_(2)O_(2)` in PRESENCE of `NaOH` `Na_(2)O_(2)` in WATER `H_(2)O_(2)` in presence of `H_(2)SO_(4)` `Na_(2)O_(2)` in presence of `H_(2)SO_(4)` SOLUTION :In Basic MEDIUM, `Fe^(3+)` will be precipitated as `Fe(OH)_(3)`.

Discussion

28.	Fe^(3+) is reduced of Fe^(2+) by using
Answer» `H_(2)O_(2)` is PRESENCE of NAOH `Na_(2)O_(2)` in water `H_(2)O_(2)` in presence of `H_(2)SO_(4)` `Na_(2)O_(2)` in presence of `H_(2)SO_(4)` Answer :A::B

Discussion

29.	Fe^(3+) does not give prussian blue colour with K_(4)[Fe(CN)_(6)] but on its reaction with (X), prussian blue colour appears (X) can be:
Answer» `MnO_(4)^(-)//H^(+)` `Zn//NaOH` `NH_(3)(AQ)` all true Solution :N//A

Discussion

30.	Fe^(3+)ions react with potassium thiocyanide to give :
Answer» yellow PPT BLUE colouration blood red colouration black ppt. Solution :`FeCl_3 + underset("POT. sulphocyanide")(3KCNS) to underset("Blood red colouration")(FE(CNS)_3) + 3KCI`

Discussion

31.	[Fe^(3+)(biphy)_(X)] , (bipy = 2,2' bipyridine)'X' value is
Answer» SOLUTION :`[FE(bipy)_(3)]^(3+)` 6 COORDINATION

Discussion

32.	Fe_(2)(SO_(4))_(3) is used in water and sewage treatment to aid the removal of suspended impurities. Calculate the mass percentage of iron, sulphur and oxygen in this compound.
Answer» Solution :`"MOL. MASS of "Fe_(2)(SO_(4))_(3)=2xx56+(32+64)xx3=400` `%" of FE"=(2xx56)/(400)xx100=28%","%" of S"=(32xx3)/(400)xx100=24%,""%" of O"=(4xx16xx3)/(400)xx100=48%`

Discussion

33.	Fe_(2)O_(3) is reduced to spongy iron near the top of blast furnace by
Answer» CO `CO_(2)` C `H_(2)` SOLUTION :C is used as reducing agent

Discussion

34.	Fe_(2)O_(3) is reduced to spongy iron near near the top of blast furnace by
Answer» `H_(2)` CAO `SiO_(2)` CO Answer :D

Discussion

35.	Fe_(2)O_(3) is converted to FeO in the presence of CO at ________
Answer» 473-573 K 573-673 K 673-773 K 773-873 K Answer :D

Discussion

36.	Fe_2(CO)_9is diamagnetic. Which of the followingreasons is correct:
Answer» PRESENCE of one CO as BRIDGE group Presence ofmonodentate ligand Metal-metal (Fe-Fe) BOND in molecule Resonance hybridisation of CO Answer :C

Discussion

37.	Fe_(2)(CO)_(9) is diamagnetic. Which of the following is the correct reason ?
Answer» One CO is present as BRIDGE group CO is a `pi`-ACCEPTOR ligand CO can form `pi`-bond with Fe by BACK bonding Metal-metal (Fe-Fe) bonding TAKES place. Solution :Metal-metal bonding pairs up the UNPAIRED electron.

Discussion

38.	Fe_(2)(CO)_(9) is diamagnetic. Which of the following reasons is correct :
Answer» Presence of one CO as bridge group Presence of MONODENTATE ligand Metal - metal (Fe-Fe) bond in molecule Resonance HYBRIDISATION of CO Solution :All electrons are PAIRD up and M-M bond is absent.

Discussion

39.	Fe_2(CO)_9 is diamagnetic. Which of the following reasons is correct:
Answer» PRESENCE of one CO as BRIDGE group Presence of MONODENTATE ligand Metal-Metal (Fe-Fe) bond in molecule Resonance HYBRIDIZATION of CO Answer :C

Discussion

40.	Fe^(2+)+NO_(3)^(-) +H_(2)SO_(4) ("conc.") to "X" (Brown ring complex) The magnetic moment of complex 'X' to its nearest integer is :
Answer» ANSWER :4

Discussion

41.	Fe^(2+) ions react with nitric oxide formed from reduction of nitrate and yields a brown coloured complex-
Answer» `[Fe(CO)_(5)NO]^(2+)` `[Fe(NH_(3))_(5)NO]^(2+)` `[Fe(CH_(3)NH_(2))_(5)NO]2^(+)` `[Fe(H_(2)O)_(5)NO]^(2+)` Answer :B::D

Discussion

42.	Fe^(2+) gives blue coloue, called(a)____ with (b)___white Fe^(2+) gives blue coloue, called(c)____ with (d)____.
Answer» ANSWER :a.Turabull's BLUE b. `K_(2)[Fe(CN)_(6)]`C. Prussium blue d. `K_(6)[Fe(CN)_(6)]`

Discussion

43.	Fe^2+ ion can be distinguished by Fe^3+ ion by:
Answer» ANSWER :C

Discussion

44.	Fe^(2+) does not give prussian blue colour with K_4[Fe((CN)_6], but on its reaction with (X), prussian blue colour appears with the reagent (X) is :
Answer» `MnO_4^(-)//H^+` `H_2SO_4` `NH_3` All true Solution :`MnO_4 H^(+) to[O] : FE^(2+)OVERSET([O])toFe^(3+)+[Fe(CN)_6]^(4-)to Fe_4[Fe(CN)_6]_3`

Discussion

45.	Fe^(2+) does not givebluecolour with K_(4)[Fe(CN)_(6)] but onitsreaction with (X) ,bluecolour oppears (X) can be
Answer» `MnO_(4)^(THETA) //H^(o+)` `H_(2)SO_(4)` `NH_(3)` `HCI` Answer :a

Discussion

46.	Fe^(2+)._((aq))+NO_(3)^(Θ)._((aq))+H_(2)SO_(4)(conc.)rarr Brown ring .The oxidationnumber of iron in brownring complex is
Answer» Solution :`[overset(+1)(Fe)(H_(2)O)_(5)overset(+1)(NO)]^(2+)SO_(4)^(2-)`

Discussion

47.	Fe^(2+) (aq)+NO_(3)^(-) (aq)+H_(2)SO_(4) (conc.) to Brown ring The brown ring is due to the formation of complex, [Fe(H_(2)O)_(5)NO]SO_(4). What is the oxidation state of iron in the complex ?
Answer» Solution :Here `NO` is `NO^(+)`, so in `[Fe(H_(2)O)_(5)NO^(+)]^(2+)`, the oxidation state of IRON is `+1`

Discussion

48.	Fe^(2+) and Fe^(3+) can be distinguished by :
Answer» `NH_(4)SCN` `CaCl_(2)` `AgNO_(3)` `H_(2)SO_(4)`. ANSWER :A

Discussion

49.	Fe ore is concentrated by :
Answer» MAGNETIC TREATMENT FROTH FLOATATION Electrolysis Roasting ANSWER :A

Discussion

50.	Fe is made passive by :
Answer» DIL.`H_(2)SO_(4)` dil. HCl conc.`HNO_(3)` conc.`H_(2)SO_(4)` SOLUTION :Chloroplatinic ACID is `H_(3)[PtCl_(6)],` which is DIBASIC

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

[Fe(CN)_6]^(4-) ion is:

[Fe(CN)_(6)]^(4-) and [Fe(H_(2)O)_(8)]^(2+) are of different colours in dilute solutions. Why

[Fe(CN)_(6)]^(4-) and [Fe(H_(2)O)_(6)]^(2+) are of different colours in dilute solutions. Why ?

[Fe(CN)_(6)]^(4-) and [Fe(CN)_(6)]^(3-) have different _________ but same _________.

[Fe(CN)_6]^(4-) and Fe(H_2 O)_6]^(2+) are different colours in dilute solutions . Why ?

[Fe(CN)_5NO]^(2-)+S^(2-)toProduct[X] Answer the following questions for the product [X]. (i)Number of negative monodenate ligand(s). (ii)Effective atomic number of iron in the complex. (iii)Number of unpaired electrons

FeCL_(3)+KI to Fe^(2+)(aq.)+KI_(3)

FeCl_3 on reaction with K_4[Fe(CN)_6] in aq solution gives blue colour and these are separated by a semi permeable membrane Due to osmosis there is

FeCl_(3) on reactiSon with K_(4)[Fe(CN)_(6)] in aq solution gives blue colour of these are separated by a semi permeable memrane AB as shown, Due to osmosis there is

FeCl_3 solution on reaction with SO_2 changes to:

FeCl_(3) and CoCl_(2) have primary valencies of

FeCl_(3) is known but not Fel_(3) Why?

FeCl_(3) has each of the following characteristics except :

FeCl_2 reacts with SO_2

FeC_3 is added separately to excess of boiling water and excess of NaOH solution, the sols obtained contain respectively the disperse particles to be :

FeC_(2)O_(4) can decolorise acidified KMnO_(4) dueto the oxidation of (a) _____and (b)____.

Fear or excitement generally cause one to breathe rapidly and it results in the decreases of concentration of CO_2 in blood. In what way it will change pHof blood :

Fe_3O_4 is known ashaematite. True or False

Fe_2O_3 is known as___-.

Fe_3O_4 is known as _____ .

Fe_(3)O_(4) is ferrimagnetic at room temperature but at 850 K it becomes :

Fe_3O_4 is ferrimagnetic at room temperature but becomes paramagnetic at 850K. Explain.

Fe_(3)O_(4) is:

Fe_3O_4 has inverse spinel structure. What is not true about this solid ?

Fe^(3+)overset(SNC^(Θ)("Excess"))rarrunderset("Bloodre"d)(A)overset(F^(ΘExcess))rarrunderset("Colourless")(B) Identify A and B (a) Write the IUPAC name of A and B (b) Find out the spin only magnetic moment of B .

Fe^(3+)overset(SCN^(-)(excess))to "blood red"(A)overset(F^(-)(excess))to"colourless"(B)Identify A and B (a) Write IUPAC name of A and B (b) Find out spin only magnetic moment of B.

Fe^(3+) is reduced to Fe^(2+) by using

Fe^(3+) is reduced of Fe^(2+) by using

Fe^(3+) does not give prussian blue colour with K_(4)[Fe(CN)_(6)] but on its reaction with (X), prussian blue colour appears (X) can be:

Fe^(3+)ions react with potassium thiocyanide to give :

[Fe^(3+)(biphy)_(X)] , (bipy = 2,2' bipyridine)'X' value is

Fe_(2)(SO_(4))_(3) is used in water and sewage treatment to aid the removal of suspended impurities. Calculate the mass percentage of iron, sulphur and oxygen in this compound.

Fe_(2)O_(3) is reduced to spongy iron near the top of blast furnace by

Fe_(2)O_(3) is reduced to spongy iron near near the top of blast furnace by

Fe_(2)O_(3) is converted to FeO in the presence of CO at ________

Fe_2(CO)_9is diamagnetic. Which of the followingreasons is correct:

Fe_(2)(CO)_(9) is diamagnetic. Which of the following is the correct reason ?

Fe_(2)(CO)_(9) is diamagnetic. Which of the following reasons is correct :

Fe_2(CO)_9 is diamagnetic. Which of the following reasons is correct:

Fe^(2+)+NO_(3)^(-) +H_(2)SO_(4) ("conc.") to "X" (Brown ring complex) The magnetic moment of complex 'X' to its nearest integer is :

Fe^(2+) ions react with nitric oxide formed from reduction of nitrate and yields a brown coloured complex-

Fe^(2+) gives blue coloue, called(a)____ with (b)___white Fe^(2+) gives blue coloue, called(c)____ with (d)____.

Fe^2+ ion can be distinguished by Fe^3+ ion by:

Fe^(2+) does not give prussian blue colour with K_4[Fe((CN)_6], but on its reaction with (X), prussian blue colour appears with the reagent (X) is :

Fe^(2+) does not givebluecolour with K_(4)[Fe(CN)_(6)] but onitsreaction with (X) ,bluecolour oppears (X) can be

Fe^(2+)._((aq))+NO_(3)^(Θ)._((aq))+H_(2)SO_(4)(conc.)rarr Brown ring .The oxidationnumber of iron in brownring complex is

Fe^(2+) (aq)+NO_(3)^(-) (aq)+H_(2)SO_(4) (conc.) to Brown ring The brown ring is due to the formation of complex, [Fe(H_(2)O)_(5)NO]SO_(4). What is the oxidation state of iron in the complex ?

Fe^(2+) and Fe^(3+) can be distinguished by :

Fe ore is concentrated by :

Fe is made passive by :

[Fe(CN)_(6)]^(4-) and [Fe(CN)_(6)]^(3-) have different _ but same _.

FeC_(2)O_(4) can decolorise acidified KMnO_(4) dueto the oxidation of (a) _and (b).

Fe^(2+) gives blue coloue, called(a)__ with (b)_white Fe^(2+) gives blue coloue, called(c) with (d).