94420 + Interview Questions in Chemistry in Class 12

1.	Electrochemical series is series of elements arranged in increasing order of their reduction potential. E_(H^(+)\|H_(2))=0. The metals abvoe H_(2) have reductioni potential, they are more reactive than hydrogen whereas metals below hydrogen are less reactive than H_(2). Reduction potentials of metal depends upon (i) sublimation energy (ii) ionization energy and hydration energy of ions. Which of the following is best oxidizing agent?
Answer» `CU^(2+)` `NA^(+)` `AG^(+)` `Al^(3+)` Answer :C

Discussion

2.	Electrochemical series is series of elements arranged in increasing order of their reduction potential. E_(H^(+)\|H_(2))=0. The metals abvoe H_(2) have reductioni potential, they are more reactive than hydrogen whereas metals below hydrogen are less reactive than H_(2). Reduction potentials of metal depends upon (i) sublimation energy (ii) ionization energy and hydration energy of ions. Whichof the following metal can be extracted by chemical reduction?
Answer» Al Mg Na Fe ANSWER :D

Discussion

3.	Electrochemical series is series of elements arranged in increasing order of their reduction potential. E_(H^(+)\|H_(2))=0. The metals abvoe H_(2) have reductioni potential, they are more reactive than hydrogen whereas metals below hydrogen are less reactive than H_(2). Reduction potentials of metal depends upon (i) sublimation energy (ii) ionization energy and hydration energy of ions. Which of the following is best reducing agent?
Answer» Li Na K Cs Answer :A

Discussion

4.	Electrochemical process is used to extract
Answer» Iron Lead Sodium Silver Answer :C

Discussion

5.	Electrochemical equivalent of an element is
Answer» `("ATOMIC MASS" xx "VALENCY")/(96500)` `("Atomic mass" xx 96500)/("Valency")` `("Atomic mass")/("Valency" xx 96500)` `("Valency" xx 96500)/("Atomic mass")` Solution :`Z = (E)/(96500) = ("At.mass")/("Valency") xx (1)/(96500)` .

Discussion

6.	Electrochemical equivalent of a substance is equal to its quantity liberated at electrode on passing electricity equal to
Answer» 1 COULOMB 96,500 coulomb 1 AMPERE 1 volt. Answer :B

Discussion

7.	Electrochemical equivalent of a substance is equal to its quantity liberated at electrode on passing electricity equal to :
Answer» 1 coulomb 1 ampere 1 volt 96,500 coulomb Answer :A

Discussion

8.	Electrochemical equivalent of a substance is 0.0006735, its eq. wt. is
Answer» 65 67.35 130 cannot be calculated Answer :A

Discussion

9.	Electrochemical equivalent of a divalent metal is 3xx10^(-4) gm/coulomb.The approximate atomic weight of the metal is
Answer» 107.8 63.6 58 55.9 Answer :C

Discussion

10.	Electrochemical cell Mg_((S))\|Mg_((aq))^(2+)(xM)\|\|Fe^(2+)(0.01M)\|Fe_((l)) has electric charge of 1.92 V then x= . . . .M E_(Mg\|\|Mg^(2+))^(@)=2.37V,E_((Fe\|Fe^(2+)))^(@)=0.45V
Answer» `x LT 0.01 M` `x=0.01M` `x GT 0.01M` No PREDICTION regarding x Solution :`E_(CELL)^(@)=E_(Mg\|Mg^(2+))^(@)-E_(Fe\|Fe^(2+))^(@)` `=2.37-0.45=1.92V` And `E_(cell)^(@)=1.92V` is given So, `E_(cell)^(@)=E_(cell)^(@)` and both half cell n=2, so both half cell has equal concentration `therefore x=0.01M=[Mg^(2+)]=[Fe^(2+)]`

Discussion

11.	Electrochemical cell is also known as ______.
Answer» SOLUTION :VOLTAIC CELL

Discussion

12.	Electro metallurgical process (electrolysis of fused electrolytc) is employed to extract
Answer» Iron Alluninium Silver Sodium Solution :Al, NA High electropositive metals can be EXTRACTED by electro metallurgical PROCESS. i.e., electrolysis of fused ELECTROLYTES

Discussion

13.	Electro-metallurgical process (electrolysis of fused electrolyte) is employed to extract
Answer» Iron Al Silver Sodium Solution :More EP metals like Na, K, Mg, Al ETC are EXTRACTING by the ELECTROLYSIS of their fused ELECTROLYTE.

Discussion

14.	Electrical resistance of mercury becomes almost zero at
Answer» 20k 10k 25k 4k Solution :Most of the METALS have their transition TEMPERATURE (i.e., the temperature at which a substance starts to BEHAVE as super conductor) in the RANGE of 2-5k.

Discussion

15.	Electrical properties of which oxide varies with the temperature ?
Answer» `TiO_2O_3` TiO MnO FEO ANSWER :A

Discussion

16.	Electrical field is used to deflect
Answer» `alpha and beta` particles `alpha and GAMMA` particles `alpha, beta and gamma` -particles `beta and gamma` particles Solution :`alpha`-particles are positively CHARGED whereas `beta-`particles are negatively charged particles. Hence, these can be deflected by ELECTRIC field. HOWEVER `gamma`-particles being neutral, so they cannot be deflected by electric field

Discussion

17.	Electrical cell that converts energy from the combusion of fuels directly into electrical energy is called
Answer» PHOTO cell fuel cell Daniel cell battery Answer :B

Discussion

18.	Electrical conductance through metals is called metallic or electronic conuctance and is due to the movement of electrons. The electronic conductance depends on
Answer» (a) the nature and structure of the METAL (b) the NUMBER of VALENCE ELECTRONS per atom (C) change in temperture (d) all of these. Answer :D

Discussion

19.	Electric furnaces are lined with magnesia because
Answer» It is not affected by ACIDS It LIBERATES oxygen on heating It MELTS at very high temperature It has no EFFECT of electricity Answer :C

Discussion

20.	Electric current is passed through two cells 'A' and 'B' in series. Cell 'A' contains an aqueous solution of Ag_(2)SO_(4) and platinum electrodes. The cell 'B' contains aqueous solution of CuSO_(4) and Cu electrodes. The current is passed till 1.6 g of oxygen is liberated at the anode of cell 'A'. (i) Give equations for the reaction taking place at each electrode. (ii) Calculate the quantities of substances deposited at the cathodes of the two cells. (Ag= 108, Cu = 63.5)
Answer» SOLUTION :`{{:(,(i),"In cell .A.,",2H_(2)O rarr O_(2)(g) + 4H^(+)+4e,"at anode"),(,,,Ag^(+) + e rarr Ag,"at cathode"),(,,"In cell .B.,",CU rarr Cu^(2+) + 2E,"at anode"),(,,,Cu^(2+) + 2e rarr Cu,"at anode"),(,(ii),"Ag = 21.6 g,",Cu = 6.35 g,):}}`

Discussion

21.	Electric furnaces are lined with magnesia because :
Answer» It is not AFFECTED by acids It liberates oxygen on heating It melts at very high temperature it has no EFFECT of electricity ANSWER :C

Discussion

22.	Electric current is passed through two cells A and B series. Cell A contains aq. AqNO_(3) and platnium electrodes while cell B contains sq. CuSO_(S) and copper electrodes.
Answer» The cathode and anode REACTIONS occuring in the two cells are different The cathode reactions in the two cells are identical but the anode reactions are different The cathode reactions in the two cells are different but the anode reactions are identical Electrolysis occurs only in CELL A and in cell B Solution :In any ELECTROCHEMICAL cell, at cathode reduction reaction and at anode oxidation reaction OCCURES.

Discussion

23.	Electric charge on 1gm ion of N^(3-) is
Answer» `4.8 xx 10^(-19)C` `10 xx 1.6 xx 10^(-19)C` `1.6 xx 10^(-19) C ` `2.89 xx 10^(5) C` ANSWER :D

Discussion

24.	El_(CB) reaction is given by which of the following A) CF_3 -CHCl_2 B) C_6H_5 - CH(NO_2)-CHBr
Answer» A only B only NEITHER A nor B Both A and B ANSWER :D

Discussion

25.	Elastomers.
Answer» Solution :Weakintermolecular forces of attraction between the polymer chains are observed in elastomers. When polymer is stressed, the polymer chain stretches and when the strain is relieved the chain returns to its original position. Elastomers are SOFT and stretchy and used in MAKING rubber BANDS. e.g. neoprene, vulcanized rubber.

Discussion

26.	Elastomers among the following are
Answer» Buna-N Buna-S NEOPRENE All Answer :D

Discussion

27.	Eka aluminium is :
Answer» Gallium Germanium Indium Scandium Answer :A

Discussion

28.	Ejection of the photoelectron from metal in the photoelectric effect experiment can be stopped by applying 0.5V when the radiation of 250nm is used. The work function of the metal is……
Answer» 4.5eV 5 eV 5.5eV 4 eV Solution :1eV= `1.602 xx 10^(-19)J`, energy to SLOP PEE= 0.5eV `((hc//lamda))/(1.602 xx 10^(-19)) (eV)= 0.5 eV+` work FUNCTION

Discussion

29.	Eka - aluminium and Eka-silicon are known as 4d^10 5 s^0. It belongs to
Answer» gallium and GERMANIUM aluminium and SILICON iron and sulphur proton and silicon SOLUTION :EKA - aluminium is known as gallium and eka-silicon is known as germanium because gallium is similar in properties to aluminium and germanium is similar in properties to silicon.

Discussion

30.	Eight mole of a gas AB_3 attain equillibrium in a closed container of volume 1 dm ^3 as 2 AB_3 hArr A_2 (g) + 3B_2 (g) if at equillibrium 2 mole of A_2 are present then calculate the equillibrium constant.
Answer» `72 mol^2L^(-2)` `36 mol^2L^(-2)` `3 mol^2L^(-2)` `27 mol^2L^(-2)` ANSWER :D

Discussion

31.	Ehichof thefollowingcompounds has beengivenanoctanenumberof 100?
Answer» n-Hexane ISO - OCTANE Neopantane NEO - Octane ANSWER :B

Discussion

32.	Eight grams of a radioactive substance is reduced to 0.5 g after 1 hour. The half life period of the radioactive substance is :
Answer» 15 min 30 min 45 min 10 min Answer :A

Discussion

33.	Eight gram each of oxygen and hydrogen at 27^(@)C will have the total kinetic energy in the ratio of …….
Answer» SOLUTION :14.439 KG

Discussion

34.	e_(g) orbitals include
Answer» `d_(XY) and d_(YZ)` `d_(yz) and d_(xz)` `d_(yz) and d_(xz)` `d_(x_(2)-y_(2)) and d_(z_(2))` ANSWER :D

Discussion

35.	Efficiency of a fuel cell is given by the expression of____.
Answer» SOLUTION :`eta=(DELTAG)/(DELTAH)xx100` or `(-NFE)/(DeltaH)xx100`

Discussion

36.	Efficiency of a catalyst depends on its :
Answer» PARTICLE size Solubility Molecular weight None Answer :A

Discussion

37.	Effective nuclear charge on last electron of Fe^(2+) (Using Slater's Rule)
Answer» 7.5 7.45 6.25 19.75 Solution :`Fe^(+2)=1s^(2)(2S^(2)2p^(6))(3s^(2)3P^(6))(3D^(6))` `sigma=0.35xx5+18xx1=1.75+18=19.75` `Z_(EN)=Z-sigma=26-19.75=6.25`

Discussion

38.	Effective collisions are those in which molecules must:
Answer» Have ENERGY equal to or GREATER than the threshold energy Have PROPER ORIENTATION ACQUIRE the energy of activation All Answer :D

Discussion

39.	Effective collision are those in which molecules must:
Answer» Have ENERGY equal to or GREATER than the threshold energy Have PROPER ORIENTATION Acquire the energy of activation All of these Solution :Activated MOLECULES should have the energy equal to (or) greater than threshold energy and proper orientation.

Discussion

40.	Effective atomic rule is used to find-
Answer» geometry of complex stability of complex number of ISOMERS of complex number ofpossible ligands arounds metal ION in complex Solution :number ofpossible ligands arounds metal ion in complex

Discussion

41.	Effective atomic number of transition metal in potassium ferrocyanide
Answer» 24 26 35 36 Answer :D

Discussion

42.	Effective atomic number of central metal ion in [Co(NH_3)_6]Cl_3 is
Answer» 24 27 35 36 Answer :D

Discussion

43.	Effect of the following groups in increasing acidity is in the order _________.
Answer» Solution :`CL lt F lt CN lt CF_(3)`

Discussion

44.	Effect of pollution is on
Answer» Linkage ECOLOGICAL BALANCE Crossing over Mutation Solution :Ecological balance is the maintenance of an equilibrium between LIVING COMPONENTS of an ECOSYSTEM. So the pollution disturbs the ecological balance

Discussion

45.	Effect of pollution is first marked on
Answer» Micro-organisms Green VEGETATION of an AREA FOOD crop None of these Answer :B

Discussion

46.	EDTA^(4-) is ethylenediaminetetraacetate ion. The total number of N-Co-O bond angles in [Co(EDTA)]^(1-) complex ion is
Answer» Solution :The complex `[Co(EDTA)]^(1-)` has the STRUCTURE as under : The N-Co-O bond angles are : (1) `angleN^(I)CoO^(I)` (2) `angleN^(I)CoO^(II)` (3) `angleN^(I)COCO^(III)` (4) `angle^(I)CoO^(IV)` (5) `angleN^(II)CoO^(I)` (6) `angleN^(II)CoO^(II)` (7) `angleN^(II)CoO^(III)` (8) `angleN^(II)CoO^(IV)` Hence, total N-Co-N bond angles = 8.

Discussion

47.	E_(Fe^(3+)//Fe^(+2))^(0)=+0.77V,E_(Fe^(+3)//Fe)^(0)=0.036V . What is E_(Fe//Fe^(+2))^(0) and is Fe^(+2)stable to disproportionation in aqueous solution under standard conditions
Answer» `+0.44 V,` yes `-0.44V`, No `+0.44 V`, No `-0.44 V`, yes Solution :`Fe^(3+)+e^(-)rarr Fe^(2+)""(1)E_(1)^(@)=0.77V" "DeltaG_(1)^(@)=-1xxFxx0.77` `Fe^(3+)+3e^(-)rarrFe""(2)E_(2)^(@)=-0.036V""DeltaG_(2)^(@)=3xxFxx0.036` `FerarrFe^(2+)+2e^(-)""(3)E_(3)=DeltaG_(3)^(@)=-2xxFxxE_(3)^(@)` `(1)-(2)=3` `DeltaG_(1)^(@)-DeltaG_(2)^(@)=DeltaG_(3)^(@)` `rArr-Fxx0.77-3F-0.036=-2xFxxE_(3)^(@)" "rArr(0.77xx0.108)=2xxE_(3)^(@)""rArrE_(3)^(@)~=0.44V Ans.` Disproportionation reaction. `3FE^(2+)rarrFe+2Fe^(3+)""(4)` `Fe^(2+)+2e^(-) rarr Fe` `E^(@)=-0.44V""DeltaG^(@)=-2xxFxx(-0.44)(5)` `Fe^(2+)rarr Fe^(3+)+e^(-)` `E^(@)=-0.77V""DeltaG^(@)=-1xxFxx(0.77)=+ve""(6)` `:'DeltaG_(4)^(@)=-2xxFxx(0.44)+2(-1xxFxx(-0.77))=+ve` `:' DeltaG_(4)^(@) GT 0,""rArr` Reaction is not SPONTANEOUS. HENCE, `Fe^(2+)` is stable to disproportiionation.

Discussion

48.	Effect of adding a non-volatie solute to a solvent is"
Answer» to lower the vapour pressure to increase the FREEZING POINT to increase the boiling point to decrease the osmotic pressure. Solution :(a,c) On adding a non-volatile SOLUTE to the solvent, the vapour pressure of the solution GETS lowered and its boiling point is reised.

Discussion

49.	EDTA^(4-) is an important ligand. Which statement about this ligand is/are true ?
Answer» It is a hexadentate ligand It can BIND through TWO OXYGEN and FOUR nitrogen atoms to a central metal ion It is a flexidentate ligand IUPAC name of the ligand is ethylenediaminetriacetato Answer :A::C

Discussion

50.	EDTA is a ……..ligand.
Answer» tetradentate Hexadentate Bidentate Tridentate Answer :B

Discussion

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Electro-metallurgical process (electrolysis of fused electrolyte) is employed to extract

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Electrical field is used to deflect

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Electric furnaces are lined with magnesia because

Electric furnaces are lined with magnesia because :

Electric current is passed through two cells A and B series. Cell A contains aq. AqNO_(3) and platnium electrodes while cell B contains sq. CuSO_(S) and copper electrodes.

Electric charge on 1gm ion of N^(3-) is

El_(CB) reaction is given by which of the following A) CF_3 -CHCl_2 B) C_6H_5 - CH(NO_2)-CHBr

Elastomers.

Elastomers among the following are

Eka aluminium is :

Ejection of the photoelectron from metal in the photoelectric effect experiment can be stopped by applying 0.5V when the radiation of 250nm is used. The work function of the metal is……

Eka - aluminium and Eka-silicon are known as 4d^10 5 s^0. It belongs to

Eight mole of a gas AB_3 attain equillibrium in a closed container of volume 1 dm ^3 as 2 AB_3 hArr A_2 (g) + 3B_2 (g) if at equillibrium 2 mole of A_2 are present then calculate the equillibrium constant.

Ehichof thefollowingcompounds has beengivenanoctanenumberof 100?

Eight grams of a radioactive substance is reduced to 0.5 g after 1 hour. The half life period of the radioactive substance is :

Eight gram each of oxygen and hydrogen at 27^(@)C will have the total kinetic energy in the ratio of …….

e_(g) orbitals include

Efficiency of a fuel cell is given by the expression of____.

Efficiency of a catalyst depends on its :

Effective nuclear charge on last electron of Fe^(2+) (Using Slater's Rule)

Effective collisions are those in which molecules must:

Effective collision are those in which molecules must:

Effective atomic rule is used to find-

Effective atomic number of transition metal in potassium ferrocyanide

Effective atomic number of central metal ion in [Co(NH_3)_6]Cl_3 is

Effect of the following groups in increasing acidity is in the order _________.

Effect of pollution is on

Effect of pollution is first marked on

EDTA^(4-) is ethylenediaminetetraacetate ion. The total number of N-Co-O bond angles in [Co(EDTA)]^(1-) complex ion is

E_(Fe^(3+)//Fe^(+2))^(0)=+0.77V,E_(Fe^(+3)//Fe)^(0)=0.036V . What is E_(Fe//Fe^(+2))^(0) and is Fe^(+2)stable to disproportionation in aqueous solution under standard conditions

Effect of adding a non-volatie solute to a solvent is"

EDTA^(4-) is an important ligand. Which statement about this ligand is/are true ?

EDTA is a ……..ligand.