94420 + Interview Questions in Chemistry in Class 12

1.	If the mole fraction of solute is 0.5 and molar mass of solvent is 50 than molality of solution will be
Answer» 20m 0.20m 2m 0.02m Solution :`m=(1000 x_(2))/(X_(1) xx M_(1))=(1000 xx 0.5)/(0.5 xx 50) =20`

Discussion

2.	Ifthe molarionicconductivities of K^(+) and I^(-)at zeroconcentrationare 73.4and76.3 Omega^(-1) cm^(2) mol^(-1) respectivelycalculatethe molarconductivityof K1at zeroconcentration
Answer» SOLUTION :` 149. 7 OMEGA^(-1)CM^(2) mol^(-1)`

Discussion

3.	If the molar conductivities at infinite dilution of NaCl, HCl and CH_(3)COONa(NaAc) are 126.4, 425.9 and 91.0 S cm^(2)mol^(-1) respectively, what will be that of acetic acid (Hac)?
Answer» Solution :According to KOHLRAUSCH's law, `wedge^(@)` for `CH_(3)COOH=lamda_(CH_(3)COO^(-))^(@)+lamda_(H^(+))^(@)` `wedge^(@)` for NaCl=`lamda_(Na^(+))^(@)+lamda_(Cl^(-))^(@)=126.4" S "cm^(2)mol^(-1)`. . . (i) `wedge^(@)` for `HCl=lamda_(H^(+))^(@)+lamda_(Cl^(-))^(@)=425.9" S "cm^(2)mol^(-1)`. . . (ii) `wedge^(@)` for `CH_(3)COONa=lamda_(CH_(3)COO^(-))^(@)+lamda_(Na^(+))^(@)=91.0" S "cm^(2)mol^(-1)`. . . (III) ADDING eqns. (ii) and (iii) and subtracting (i), we get `lamda_(H^(+))^(@)+lamda_(Cl^(-))^(@)+lamda_(CH_(3)COO^(-))^(@)-lamda_(Na^(+))^(@)-lamda_(Na^(+))^(@)-lamda_(Cl^(-))^(@)=425.9+91.0-126.4" S "cm^(2)mol^(-1)` or `lamda_(CH_(3)COO^(-))^(@)+lamda_(H^(+))^(@)=390.5" S "cm^(2)mol^(-1)` i.e., `wedge^(@)` for `CH_(3)COOH=390.5" S "cm^(2)mol^(-1)`.

Discussion

4.	If the molar conductivities at infinite dilution at 293K for aqueous hydrochloric acid, sodium acetate and sodium chloride solution are 383.5, 78.4 and 102.0 S cm^(2) respectively, calculate themolar conductivity or acetic acid at this temperature and dilution. if the molar conductivity of acetic acid at some other dilution is 100.0 S cm^(2) at 293K, calculate the degree of ionization of acetic acid at this dilution.
Answer» ANSWER :`WEDGE^(@)=359.9" S "CM^(2),alpha=0.278`

Discussion

5.	If the messenger shaped drug is used then receptor accept it and under the impression of natural messenger the communication process occurs, such drugs are called ........
Answer» antagonists allosteric AGONISTS enzyme INHIBITORS SOLUTION :agonists

Discussion

6.	If the masses of Cr and O are in the ratio 13:12Cr_2O_3, then the ratio of O that cobines with the same mass of Cr in Cr_2O_3 and Cr_2O_7 is
Answer» `1 : 2` `1 : 4` `3 : 7` `2 : 5` ANSWER :C

Discussion

7.	If the mass defet of ""_(4)^(9)X is 0.090 amu, their binding energy per nucleon is (1 amu = 931.5 MeV)
Answer» 9.315 MEV 931.5 MeV 83.0 MeV 8.38 MeV SOLUTION :BINDING ENERGY per nucleon = `(931.5)/(9)` `= 9.314 MeV`.

Discussion

8.	If the mass of 1 mole of water containing x % of heavy water is 19 g then the value of 'x is
Answer» 0.3 0.5 0.75 0.62 Solution :Out of 1 mol of water ,NUMBER of MOLES of `D_2O = (x)/(100) xx 1 = 0.01 x` Number of moles of `D_2O xx ` mass of `D_2O + `number of moles of `H_2O xx ` mass of `H_2O = 19` `0.01 x xx 20 +(1 - 0.01 x) xx 18 = 19` `0.01 x xx 20 + 18 - 0.01x xx 18 = 19` ` 2 xx 0.01 x = 1` x= 50

Discussion

9.	If the mass defect of ""_(4)^(9)X is a.m.u., then binding energy per nucleon is (1 a.m.u. = 931.5 MeV):
Answer» 9.315 MeV 931.5 MeV 83.8 MeV 8.38 MeV. Solution :Binding energy `=0.09xx931.5` MeV Binding energy per NUCLEON `=(0.09xx931.5)/(9)` MeV, =9.315 MeV

Discussion

10.	In electrorefining of metal the impure metal is made the anode and strip of pure metal the cathode during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for refining of
Answer» Silver Copper Aluminium Gold Answer :C

Discussion

11.	In electrorefining of coppersome gold isdeposited at
Answer» CATHODE ANODE MUD cathode electrode SOLUTION :Duringelectrorefiningof COPPER,gold isdepositedintheanodemud.

Discussion

12.	In electroplating, the article to be electroplated serves are
Answer» Cathode Electrolyte Anode Conductor Answer :A

Discussion

13.	In electrorefiningof copper , pure copper is obtained :
Answer» at CATHODE at ANODE in the ELECTROLYTE in anode MUD ANSWER :A

Discussion

14.	In electroplating copper with silver the bath solution used is of K[Ag(CN)_2] instead of AgNO_3 because on account of complex formation.
Answer» A thinner COATING of silver is OBTAINED Availability of `Ag+` ions in SOLUTION is so reduced that they are not replaced by copper ions `Ag+` ions are completely removed from the solution Expense on electricity are reduced Answer :B

Discussion

15.	In electrophlaing , the metal that is not used for plating is
Answer» Fe Zn Ni Au Answer :A

Discussion

16.	In electrophilic substitution reactions of haloarenes, halogen atom is
Answer» SLIGHTLY ACTIVATING and o, p-directing Slightly DEACTIVATING and META directing Slightly activating and meta directing Answer :C

Discussion

17.	In electronic watch zinc/silver oxidation cell is used, which gives following reactioni : Zn^(2+)+2e^(-) to Zn,E^(@)=-0.760V Ag_(2)O+H_(2)O+2e^(-) to 2Ag+2OH^(-),E^(@)=0.344V If F=96500 C mol^(-1) then find out DeltaG^(@)of cell.
Answer» 113.072 KJ `mol^(-1)` 213.072 kJ `mol^(-1)` `313.082" kJ "mol^(-1)` 413.021 kJ `mol^(-1)` SOLUTION :`E_(cell)^(0)=0.344-(-0.76)=1.104` `DeltaG^(@)=-nFE_(cell)^(@)` `=-2xx96500xx1.104` `=213072" J "mol^(-1)=213.072` kJ/mol

Discussion

18.	In electrophilic aromatic substitution reaction, the nitro group is meta directing because it :
Answer» decreases ELECTRON density at meta POSITION increases electron density at meta position increases electron density at ortho and PARA POSITIONS decreases electron density at ortho and para positions SOLUTION :

Discussion

19.	In electron capture (radioactive process):
Answer» a neutron is formed a PROTON is CONSUMED `GAMMA` -ray emission TAKE place X-ray emission takes place Answer :A::B::D

Discussion

20.	In electrometallurgy of aluminium, why is the graphite rod used?
Answer» Solution :(1) In the electrometallurgy, aluminium is obtained by the electrolysis of fused electrolyte of alumina `(Al_(2)O_(3))` in cryolite and `CaF_(2).` (2) At high temperature, the carbon rods are used as anode which give high efficiency of electrolytic process. (3) During electrolysis `O_(2)` is LIBERATED by the REACTION of `F_(2)` formed at anode with alumina, `Al_(2)O_(3)`. This OXYGEN reacts with carbon forming CO and further `CO_(2)`.

Discussion

21.	In electrolytic refining the impure metal is used to make
Answer» Cathode ANODE Electrolytic bath None of these Solution :IMPROVE METAL as anode and PURE metal as CATHOD.

Discussion

22.	In electrolytic refining, the impure metal is made
Answer» cathode anode both none of the above ANSWER :B

Discussion

23.	In electrolytic refining of metals, electrolysis of an aqueous solution of its complex salt is done with impure metal as anode and a strip of pure metal as cathode. This method cannot be used for the refining of the metal
Answer» SILVER Copper Aluminium Zinc Answer :D

Discussion

24.	In electrolytic refining of lead, Sb, Cu, Ag and Au are found:
Answer» on ANODE in ELECTROLYTE SOLUTION in anode mud in CATHODE mud Answer :C

Discussion

25.	In electrolyticrefining of lead, relectrolyte consists of:
Answer» `H_(2)SiF_(6)` only `Pb_(2)SiF_(6)` only `H_(2)SiF_(6) "only"` `H_(2)SiF_(6) and PnSiF_(6)` Answer :D

Discussion

26.	In electrolytic refining of copper, what would be the anode?
Answer» SOLUTION :IMPURE COPPER will ACT as ANODE.

Discussion

27.	In electrolytic cell, if Cl_(2) gas at anode and H_(2) gas at cathode liberated, then in such cell. . . . Solution is present.
Answer» Aqueous solution of `FeCl_(3)` Concentrated solution of NACL Solution of `CuCl_(2)` Solution of `ZnCl_(2)` Solution :Concentrated solution of NaCl On cathode : `Na^(+)+2E^(-) +2H^(+) to 2Na^(+)+H_(2(g))` `underline("On ANODE : "2Cl_((a))^(-) to Cl_(2(g))+2e^(-))` `2Na^(+)+2Cl^(-) +2H^(+) to Cl_(2)+H_(2)+2Na^(+)`

Discussion

28.	In electrolytic cell, cathode acts as an/a
Answer» Oxidising agent REDUCING agent Either of the two Neither (a) nor (b) Solution :Electrolytic CELL, cathode acs as a reducing agent. E.g., At cathode, `Na^(+)+e^(-)TONA` (reduction) At anode: `underline("Cl^(-)toCl+e^(-)("oxidation")"")` `Na^(+)+Cl^(-)tounderset(("Cathode"))(Na)+underset(("anode"))(Cl)`

Discussion

29.	In electrolytic cell, reduction occurs at ..........
Answer» SOLUTION :CATHODE

Discussion

30.	In electrolysis, oxidation takes place at:
Answer» ANODE Cathode Both at the anode as WELL as cathode The SURFACE of ELECTROLYTE solution Answer :A

Discussion

31.	In electrolysis of water under alkaline conditions a total of 1 mole of gases is evolved . The amount of water decomposed would be
Answer» 2 mol 1 mol 2/3 mol 1/3 mol Solution :`H_2 O to H_(2(G))+(1)/(2)O_(2(g))` 1 mole of water =1.5 mole of gas `THEREFORE` 1 mole of gas =`(1)/(1.5) = 0.66 = (2)/(3)` mol. of water should be DECOMPOSED.

Discussion

32.	In electrolysis , oxidation takes place at
Answer» anode CATHODE both at the anode as well as cathode the surface of electrolyte solution Solution :Anode is ELECTRODE at which OXIDATION OCCURS .

Discussion

33.	In electrolysis of dil. H_(2)SO_(4) the ratio by weight of gases evolved at anode and cathode respectively are
Answer» `1:16` `8:1` `16:1` `3:1` SOLUTION :In the electrolysis of DIL. `H_(2)SO_(4)` the electrolysis takes PLACE as `H_(2)O hArr H^(+)+OH^(-)` At anode `"" 2OH^(-) to H_(2)O+[O]+2e^(-)` At cathode `"" 2H^(+)+2e^(-) to 2[H]` `therefore W+[O]:W+2[H^(+)] therefore 16:2 therefore 8:1`

Discussion

34.	In electrolysis of NaCl when Pt electode is taken then H_2 is liberated at cathode while with Hg cathode, it forms sodium amalgam. This is because
Answer» Hg is more inert than Pt More VOLTAGE is REQUIRED to reduce `H^(+)` at Hg than at Pt Na is DISSOLVED in Hg while it does not dissolve in Pt Conc. of `H^(+)` IONS is larger when Pt electrode is taken Answer :B

Discussion

35.	In electrolysis of dilute H_(2)SO_(4) using platinum electrodes
Answer» `H_(2)` is evolved at cathode `NH_(3)` is produced at anode `Cl_(2)` is obtained at cathode `O_(2)` is produced Solution :When platinum ELECTRODES are dipped in dilute solution `H_(2)SO_(4)` than `H_(2)` is evolved at cathode.

Discussion

36.	In electrolysis of dil. H_(2) SO_(4) using platinum electrodes:
Answer» `H_(2)` is EVOLVED at cathode `SO_(2)` is produced at ANODE `O_(2)` is OBTAINED at cathode `SO_(2)` is produced at cathode Answer :C

Discussion

37.	In electrolysis of a fused salt, the weight of the deposite on an electrode will not depend on …………….
Answer» temeperature of the bath current INTENSITY electro chemical EQUIVALENT of IONS time for ELECTROLYSIS ANSWER :A

Discussion

38.	In electroefining of copper a minor percentage of gold accumulates in
Answer» Anode MUD Cathode mud Electrolyte Cathode. SOLUTION :We know `W=Zlrtherefore t=(W)/(Zl)` `=(2xx96500xx2)/(63.5xx0.5)=12157.68s`.

Discussion

39.	In electrolysis of a fused salt, the weight deposited on an electrode will not depend on:
Answer» TEMPERATURE of the bath Current intensity Electrochemical EQUIVALENT of ions Time for electrolysis Answer :A

Discussion

40.	In electrochemical corrosion of metals, the metal undergoing corrosion:
Answer» ACTS as anode Acts as cathode Is reduced Either of these Answer :A

Discussion

41.	In electro-refining of metal the impure metal is made the anode and a strip of pure metal, the cathode, during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for retining of
Answer» silver copper aluminium sodium Solution :NA reacts VIGOROUSLY with WATER (exothermic PROCESS )

Discussion

42.	In electro-refining of metal the impure metal is made the anode and a strip of pure metal the cathode during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for refining of:
Answer» silver Copper Aluminium Sodium Answer :B

Discussion

43.	In electric bulbs...........inert gas is present with N_(2) gas.
Answer» SOLUTION :ARGON (AR)

Discussion

44.	In elastomeric polymers, the polymer chains are held together by the____________ intermolecular forces.
Answer» SOLUTION :WEAKEST

Discussion

45.	In elastomers intermolecular forces are
Answer» WEAK STRONG very strong nil Answer :A

Discussion

46.	In Elaster, intermolecular force are
Answer» NIL WEAK STRONG Very strong ANSWER :B

Discussion

47.	In elastomer, intermolecular forces are
Answer» strong weak nil none of these Solution :Elastomers are the POLYMERS having very weak intennolecular forces of ATTRACTION between the POLYMER chain. The weak forces PERMIT the polymer to be stretched.

Discussion

48.	In E.Coli DNA, the AT/GC ratio is 0-93. If the number of moles of adenine in the DNA sample is 465,000, calculate the number of moles of guanine present.
Answer» Solution :Since the number of MOLES of adenine MUST be equal to that of thymine, therefore , `(A+T)=465,000+465,000=930,000`. Since `(A+T)//(C+G)=0.93`, therefore, number of moles of `C+G=(930,000)/(0.93)=10,00,000` Further since the number of moles of C=number of MOLECULE of G. `therefore` No. of moles of GUANINE (G)`=1000,000//2=500,000`.

Discussion

49.	In Each unit cell of NaCl chlorine atoms are present at 14 lattice points then at how many lattice point, 'Na' will be present -
Answer» 13 NA ATOMS 14 Na atoms 6 Na atoms 8 Na atoms ANSWER :A

Discussion

50.	In each of the following two questions two statements are given one labelled as the Assertion(A) or Statement I and the other labelled as the reason (R) or statement II. Examine these statements carefully and mark the correct choice as per following instructions Assertion (A) - In a gaseous reaction, the ratio by volumes of reactant and gaseous products is in agreement with their molar ratio Reason (R) - Volume of gas is inversely proportional to its number of moles at particular temperature and pressure.
Answer» Both A and R are true and R is the correct EXPLANATION of A Both A and R are true but R is not a correct explanation of A A is true but R is false A is false but R is true Answer :C

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

If the mole fraction of solute is 0.5 and molar mass of solvent is 50 than molality of solution will be

Ifthe molarionicconductivities of K^(+) and I^(-)at zeroconcentrationare 73.4and76.3 Omega^(-1) cm^(2) mol^(-1) respectivelycalculatethe molarconductivityof K1at zeroconcentration

If the molar conductivities at infinite dilution of NaCl, HCl and CH_(3)COONa(NaAc) are 126.4, 425.9 and 91.0 S cm^(2)mol^(-1) respectively, what will be that of acetic acid (Hac)?

If the messenger shaped drug is used then receptor accept it and under the impression of natural messenger the communication process occurs, such drugs are called ........

If the masses of Cr and O are in the ratio 13:12Cr_2O_3, then the ratio of O that cobines with the same mass of Cr in Cr_2O_3 and Cr_2O_7 is

If the mass defet of ""_(4)^(9)X is 0.090 amu, their binding energy per nucleon is (1 amu = 931.5 MeV)

If the mass of 1 mole of water containing x % of heavy water is 19 g then the value of 'x is

If the mass defect of ""_(4)^(9)X is a.m.u., then binding energy per nucleon is (1 a.m.u. = 931.5 MeV):

In electrorefining of metal the impure metal is made the anode and strip of pure metal the cathode during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for refining of

In electrorefining of coppersome gold isdeposited at

In electroplating, the article to be electroplated serves are

In electrorefiningof copper , pure copper is obtained :

In electroplating copper with silver the bath solution used is of K[Ag(CN)_2] instead of AgNO_3 because on account of complex formation.

In electrophlaing , the metal that is not used for plating is

In electrophilic substitution reactions of haloarenes, halogen atom is

In electronic watch zinc/silver oxidation cell is used, which gives following reactioni : Zn^(2+)+2e^(-) to Zn,E^(@)=-0.760V Ag_(2)O+H_(2)O+2e^(-) to 2Ag+2OH^(-),E^(@)=0.344V If F=96500 C mol^(-1) then find out DeltaG^(@)of cell.

In electrophilic aromatic substitution reaction, the nitro group is meta directing because it :

In electron capture (radioactive process):

In electrometallurgy of aluminium, why is the graphite rod used?

In electrolytic refining the impure metal is used to make

In electrolytic refining, the impure metal is made

In electrolytic refining of metals, electrolysis of an aqueous solution of its complex salt is done with impure metal as anode and a strip of pure metal as cathode. This method cannot be used for the refining of the metal

In electrolytic refining of lead, Sb, Cu, Ag and Au are found:

In electrolyticrefining of lead, relectrolyte consists of:

In electrolytic refining of copper, what would be the anode?

In electrolytic cell, if Cl_(2) gas at anode and H_(2) gas at cathode liberated, then in such cell. . . . Solution is present.

In electrolytic cell, cathode acts as an/a

In electrolytic cell, reduction occurs at ..........

In electrolysis, oxidation takes place at:

In electrolysis of water under alkaline conditions a total of 1 mole of gases is evolved . The amount of water decomposed would be

In electrolysis , oxidation takes place at

In electrolysis of dil. H_(2)SO_(4) the ratio by weight of gases evolved at anode and cathode respectively are

In electrolysis of NaCl when Pt electode is taken then H_2 is liberated at cathode while with Hg cathode, it forms sodium amalgam. This is because

In electrolysis of dilute H_(2)SO_(4) using platinum electrodes

In electrolysis of dil. H_(2) SO_(4) using platinum electrodes:

In electrolysis of a fused salt, the weight of the deposite on an electrode will not depend on …………….

In electroefining of copper a minor percentage of gold accumulates in

In electrolysis of a fused salt, the weight deposited on an electrode will not depend on:

In electrochemical corrosion of metals, the metal undergoing corrosion:

In electro-refining of metal the impure metal is made the anode and a strip of pure metal, the cathode, during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for retining of

In electro-refining of metal the impure metal is made the anode and a strip of pure metal the cathode during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for refining of:

In electric bulbs...........inert gas is present with N_(2) gas.

In elastomeric polymers, the polymer chains are held together by the____________ intermolecular forces.

In elastomers intermolecular forces are

In Elaster, intermolecular force are

In elastomer, intermolecular forces are

In E.Coli DNA, the AT/GC ratio is 0-93. If the number of moles of adenine in the DNA sample is 465,000, calculate the number of moles of guanine present.

In Each unit cell of NaCl chlorine atoms are present at 14 lattice points then at how many lattice point, 'Na' will be present -