94420 + Interview Questions in Chemistry in Class 12

1.	The arrangement ABC ABC….is referred to as
Answer» OCTAHEDRAL CLOSE PACKING HEXAGONAL close packing tetrahedral close packing cubic close packing ANSWER :D

Discussion

2.	The aromatic compounds present as particulates are :
Answer» Benzene Toluene Nitrobenzene Polycyclic hydrocarbons Answer :B

Discussion

3.	The aromatic compounds is present as particulates are
Answer» Benzene Toluene Nitrobenzene Polycyclic hydrocarbon Answer :D

Discussion

4.	The aromatic compounds having formula C_(7)H_(8)O which are easily ientifiable by FeCl_(3) solution test (violet colouration) are
Answer» o-cresol and benzyl alcohol mj-cresol and p-cresol o-cresol and p-cresol methyl phenyl ether and benzyl alcohol Solution :o-Cresol is a PHENOL and HENCE GIVES VIOLET colourr with `FeCl_(3)` while benzyl alcohol being an alcohol does not.

Discussion

5.	The Arrhenius equation expressing the effect of temperature on the rate constant of reaction is
Answer» `K=Ea//RT` `K=A" "e^(-Ea//RT)` `K="LOGE"(Ea)/(RT)` `K=e^(-Ea//RT)` Answer :B

Discussion

6.	The aqueous solutions of the following substances were electrolysed. In which case, the pH of the solution does not change if inert electrodes are used.
Answer» `AgNO_(3)` `CuSO_(4)` NACL `K_(2)SO_(4)` Answer :D

Discussion

7.	The aqueous solutions of sodium formate , anilinium chloride and potassium cyanide are respectively ………..
Answer» acidic , acidic , basic basic , acidic , basic basic , neutral , basic none of these Solution :basic , acidic , basic `HCOONA + H - OH = hArr underset("strong base")(NaOH) + H - underset("WEAK ACID")(C OOH)` Basic in NATURE `C_(6) H_(5) NH_(3) CL^(-) + H - O hArr underset("acidic")(H_(3) O^(+)) + C_(6) H_(5) - NH_(2) + Cl^(-)` `underset("basic") (KCN) + H- OH hArr underset("strong base")(KOH) + underset("weak acid")(HCN)`

Discussion

8.	The aqueous solutions of sodium formate, anilinium chloride and potassium cyanide are respectively
Answer» ACIDIC, acidic, basic basic, acidic, basic basic, NEUTRAL, basic none of these Answer :B

Discussion

9.	The aqueous solutions of the following salts will be coloured in case of
Answer» `ZN (NO_(3))_(2)` `CO(NO_(3))_(2)` `CrCl_(3)` both `Co(NO_(3))_(2)and CrCl_(3)` Answer :D

Discussion

10.	The aqueous solutions, containing respectively 7.5 g of urea (mol. Wt = 60) and 42.75 g substance X in 100 g of water freeze at the same temperature. Calculate the molar mass of X.
Answer» SOLUTION :`DeltaT_(F)=K_(f)xxm." As "DeltaT_(f)` is same for the TWO solution, their molalities will be equal, i.e., `(7.5)/(60)XX(1000)/(100)=(42.75)/(M)xx(1000)/(10) or M=342.`

Discussion

11.	The aqueous solution of which vitamin is darkpink in colour:
Answer» `B_1` `B_2` `B_6` `B_12` ANSWER :D

Discussion

12.	The aqueous solution of which one of the following is basic
Answer» HOCl `NaHCO_(4)` `NH_(4)NO_(3)` `NAOCL` SOLUTION :NaOCl is a mixture of strong base and WEAK acid.

Discussion

13.	The aqueous solution of urea has freezing point -0.6^(@)C. To prepare such solution how much gram of urea is needed to dissolve in 3 kg of water ? (M = 60 gm/mol) (K_(f)=1.5^(@)C" kg mol"^(-1)).
Answer» ANSWER :72 GM

Discussion

14.	The aqueous solution of which of the following salt has the lowest pH
Answer» NaClO `NaClO_(2)` `NaClO_(3)` `NaClO_(4)` Solution :`NaClO_(4)` is a salt of strong ACID `HClO_(4)`. So it is a strong acid salt.

Discussion

15.	The aqueous solution of transition metal salt changes colour from pink to blue, when concentrated hydrochloric acid is added to it. The changes in colour is due to:
Answer» EVOLUTION of hydrogen that CHANGES the OXIDATION state of the METAL ion change in the coordination number of the metal ion from 6 to 4 and formation of new species in solution formation of a coordination complexof the metal ion with hydrochloric acid protonation of the metal ion Answer :B

Discussion

16.	The aqueous solution of the following salts will be coloured in the case of
Answer» `Zn(NO_(3))_(2)` `LiNO_(3)` `CrCl_(3)` Potash alum Solution :`CrCl_(3)`, as `Cr^(+3) implies3d^(3)`, has unpaired electron in d-orbital as a result it will show PARAMAGNETISM and THUS forms coloured COMPLEXES.

Discussion

17.	The aqueous solution of the following salt will be coloured in the case of :
Answer» `Zn(NO_3)_2` `LiNO_3` `Co(NO_3)_2` `CrCl_3` Solution :Compunds with UNPAIRED `E^-` shows colours `Cu^+2=[AR] 3d^9 ,MN^(+2)=[Ar]3d^5`

Discussion

18.	The aqueous solution of sugar does not conduct electricity whereas when sodium chloride is added to water, it conducts electricity. Justify this statement.
Answer» Solution :`` SUGAR is a non electrolyte and when it dissoves in water, there will be no ionisation takes PLACE . If there is no FREE ions, it does not conduct electricity. `` When sodium chloride is added to water, it is completely ionised to give `Na^(+)` ions and `Cl^(-)` ions. DUE to the presence of ions, they will be possibility of electrical conductance. Becuase ions are carriers of electric current.

Discussion

19.	The aqueous solution of sodium acetate with minimum pH is
Answer» `0.01 M` `0.001 M` `0.0001 M` `0.1 M` SOLUTION :`CH_(3)COONa` is a salt of weak acid `(CH_(3)COOH)` and strong BASE `(NaOH)`. So `CH_(3)COONa` is a strong base.

Discussion

20.	The aqueous solution of sodium formate, anilinium chloride and potassium cyanide are respectively…..
Answer» acidic,acidic,BASIC basic,acidic,basic basic,neutral,basic none of these Solution :`HCOONa+H-OH leftrightarrowNaOH_(STRONG base)+H-COOH_( weak acid)` Basic in NATURE `C_6H_5NH_3Cl^(-)+H-OH leftrightarrowH_3O_(acidic)^(+)+C_6H_5^(-)-NH_2+Cl^(-)` `KCN_(basic)+H-OH leftrightarrow KOH_(strong base)+HCN_(weak acid)`

Discussion

21.	The aqueous solution of salt gives white ppt with lead acetate solution which is insoluble in hot water and nitric acid. The salt contains
Answer» `Cl^(-)` `Ba^(+ +)` `CO_(3)^(2-)` `SO_(4)^(2-)` SOLUTION :`PB(CH_(3)-COO)_(2)+SO_($)^(2-) to underset("White ppt")(PbSO_(4)) darr +2CH_(3)-COO^(-)`, `PbSO_(4)` is insoluble in water and `HNO_(3)`

Discussion

22.	The aqueous solution of saltgives white ppt withlead aceetate solution whichis insolution inbut water and nitricacid .The salt contains
Answer» `CI^(Θ)`<BR>`Br^(2+)` `CO_(3)^(2+)` `SO_(4)^(2-)` SOLUTION :`PbSO_(4)` is white and insoluble in `HNO_(2) `and hotwater

Discussion

23.	The aqueous solution of RCOOH contains,
Answer» `RCOO^(-) + H^(+)` `RCO^(+) + OH^(-)` `RCOO^(-) + H_(3)O^(+)` `RCOOH + RCOO^(-) + H_(3)O^(+)` Answer :D

Discussion

24.	The aqueous solution of following salt will have the lowestpH :
Answer» `NaClO_4` `NaClO_2` `NACLO` `NaClO_3` SOLUTION :`NaCIO_4` reacts with water to PRODUCE NAOH and `HCIO_4` `HCIO_4` being a strong acid has LOWER pH

Discussion

25.	The aqueous solution of disodium hydrogen phosphate is :
Answer» Acidic Neutral Basic None of these Answer :C

Discussion

26.	The aqueous solution of each of the following salt is coloured except
Answer» `TiCl_(4)` `FeCl_(3)` `CuCl_(2)` `MnCl_(2)` Answer :A

Discussion

27.	The aqueous solution of CuSO_(4) is
Answer» Acidic Basic Neutral Amphoteric Solution :`CuSO_(4)` is a salt of WEAK base, `(Cu(OH)_(2))` and strong ACID `(H_(2)SO_(4))`.

Discussion

28.	The aqueoussolution of (C) on treatment with conc. H_(2)SO_(4) gives a orange coloured compound (E).
Answer» Answer : The ors is chromite `FeOCr_(2)O_(3)`. `2Na_(2)CrO_(4)+UNDERSET((E))(H_(2)SO_(4))rarr Na_(2)Cr_(2)O_(7)+Na_(2)SO_(4)+H_(2)O`

Discussion

29.	The aqueous solution of copper(II) sulphate is slowly hydrolysis forming basic copper sulphate whose chemical composition is:
Answer» `CuSO_(4)CU(OH)_(2)` `CuSO_(4)CUO` `CuSO_(4)Cu(OH)_(2)CuO` `[Cu(H_(2)O)_(4)]SO_(4)*H_(2)O` Answer :A

Discussion

30.	The aqueous solution of an acid is characterised by the presence of :
Answer» `OH^-` IONS `H_3O^+` ions `H^+` ions `H_4O^+` ions Answer :B

Discussion

31.	The aqueous solution of aluminium chloride is acidic due to
Answer» Cation HYDROLYSIS Anion hydrolysis Hydrolysis of both anion and cation DISSOCIATION SOLUTION :`Al^(+++)` of `AlCl_(3)` undergoes hydrolysis.

Discussion

32.	The aqueous solution of aluminium chloride is acidic due to :
Answer» ANION HYDROLYSIS Formation of `AL(OH)_(3)` Hydrolysis of CATION and anion CATIONIC hydrolysis Answer :D

Discussion

33.	The aqueous solution of AlCl_(3) is acidic due to the hydrolysis of
Answer» ALUMINIUM ION CHLORIDE ion Both aluminium and chloride ion NONE of these Answer :A

Discussion

34.	The aqueous solution of a nitrogen and chlorine containing organic compound (A) is acidic to litmus. (A) on treatment with aqueous NaOHgives a compound (B) on treatement with C_(6)H_(5)SO_(2)CI in the presence of NaOH gives an insoluble product (C) C_(13)H_(13)NO_(2)S. give the structures of (A) and (B).
Answer» SOLUTION :`(A)rArrPh-underset(CH_(3))underset(\|)overset(o+)NH_(2)]CI^(Theta) (B) rArrPh-NH-CH_(3)` `C rArrPh-underset(CH_(3))underset(\|)N-overset(O)overset(\|\|)underset(O)underset(\|\|)(S)-PH ("Insoluble in" NaOH)`

Discussion

35.	The aqueous solution of a salt gives white ppt. with lead acetate solution which is insoluble in hot water and nitric acid . The salt contains :
Answer» `Cl^(-)` `BA^(2+)` `SO_4^(2-)` `SO_3^(2-)` . SOLUTION :`Na_2SO_4 + (CH_3COO)_2 PB to UNDERSET("Insoluble")(PbSO_4) + 2CH_3COONa `

Discussion

36.	The aqueous solution of a nitrogen and chlorine containing compound (A) is acidic to litmus. (A) on treatment with aqueous NaOH gives a compound (B) containing nitrogen, but not chlorine. Compound (B) on treatment with C_(6)H_(5)SO_(2)Cl in presence of NaOH gives an isoluble product (C) C_(13)H_(13)NO_(2)S. Give structure of (A) and (B).
Answer» Answer :`"Aminhydrochloride"hArr"AMINE",Hcloverset(NaOH)rarr"Amine")+H_(2)O+NaCl` `A=[C_(6)H_(5)NH_(2)CH_(3)]Cl^(-)` and `B=C_(6)H_(5)NHCH_(3)`

Discussion

37.	The aqueous solution of a complex compound having the formula coBrCl_(2).4NH_(3)conducts electricity and also gives white precipitate with AgNO_(3). Write the IUPAC notation and IUPAC name of the compound.
Answer» SOLUTION :`[CO(NH_(3))_(4)BrCl]CL` similar to

Discussion

38.	The aqueous solution of a certain compound (X), when added to a copper sulphate solution, a brown precipitate is obtained which tums white on addition of excess of Na_(2)S_(2)O_(3) solution. Its aqueous solution, when added to Ag^(+) ion solution, a yellow curdy precipitate is obtained which is insoluble in ammonium hydroxide. Hence, compound (X) is
Answer» NaBr KBr Kl `PbCrO_(4)` Solution :(X) is Kl `l^(-)+AG^(+)UNDERSET("Yellow ppt.")(toAgl)` `CuSO_(4)+underset((X))(2Kl)to"Cul"_(2)+K_(2)SO_(4)` `"2Cul"_(2)underset("Brown ppt.")(toCu_(2)l_(2))darr+l_(2)` `Na_(2)S_(2)O_(3)+l_(2)toNa_(2)S_(4)O_(6)+2Nal` Hence,(C) is the correct answer.

Discussion

39.	The aqueous solutio of a inorganic compound (X) yielded a white precipitated when treated with dil HNO_(3) and AgNO_(3) . Another sample of solution of (X) when treated with NaOH gas a white precipitate first which dissolved in excess of NaOH yielding a colorless solution. Whne H_(2)S gas was passed through that ssolution and white precipitate was obtained. Identify the compound (X) and give the reactions.
Answer» Solution :`UNDERSET((X))(ZnCl_(2))+2AgNO_(3)underset("WHITE")(2AgCl DARR)+Zn(NO_(3))_(2)` `ZnCl_(2)+2NaOH rarr underset("White")(Zn(OH)_(2)darr)+2NaCl` `Zn(OH)_(2)+2NaOHrarr underset("Colourless "sol^(n))(Na_(2)ZnO_(2))+2H_(2)O` `Na_(2)ZnO_(2)+H_(2)S underset("White")(ZnS darr) +2NaOH`

Discussion

40.	The aqueous solution containing which one of the following ions will be colourless (Atomic number Sc=21, Fe=26, Ti=22, Mn=25)
Answer» `Sc^(3+)` `FE^(2+)` `Ti^(3+)` `Mn^(2+)` SOLUTION :`._(21)Scrarr1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(2)3d^(1).` `Sc^(+3)rarr1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)` Due to absence of ELECTRON it will be colourless.

Discussion

41.	The aqueous solution containing which one fo the following ions will be colourless ?
Answer» `Sc^(3+)` `Fe^(2+)` `Ti^(3+)` `Mn^(2+)` SOLUTION :`Sc^(3+)` AQUEOUS solution will be colourless because of `3d^(0)` configuration.

Discussion

42.	The approximate time duration in hours to electroplate 30 g of calcium from molten calcium chloride using a current of 5 amp is [At. Mass of Ca=40]
Answer» 8 80 10 16 Answer :A

Discussion

43.	The aqeous solution of which of the following salt will have the lowest pH ?
Answer» `NACLO` `NaClO_2` `NaClO_3` `NaClO_4` ANSWER :D

Discussion

44.	The aqueous solution containing which one of the following ion will be colourless ?
Answer» `Sc^(3+)` `Fe^(2+)` `TI^(3+)` `MN^(2+)` ANSWER :A

Discussion

45.	The approximate time duration in hours to electroplate 30 g of calcium from molten calcium chloride using a current of 5 amp is [At., mass of Ca = 40]
Answer» 8 80 10 16 Solution :`w = Z xx IXX t` `30 = (Eq. wt)/(96500) xx 5 xx t` Eq. wt = `(40)/(2) "" [CA^(2+) + 2 e^(-) to Ca]` `30 = (40)/(2 xx 96500) xx 5 xx t` `t = (30 xx 2 xx 96500)/( 40 xx 5)` `t = 28950 s = (28950)/(3600) = 8` HOURS

Discussion

46.	The approximate percentage of iron in mischmetal is :
Answer» 10 20 50 5 Answer :D

Discussion

47.	The approximate of benzene in 90%
Answer» 0.4 0.7 0.65 0.5 Solution :N/A

Discussion

48.	The approximate mass of an electron is 10^(-27) g. Calculate the uncertainty in its velocity if the uncertainty in its position were of the order of 10^(-11) m
Answer» SOLUTION :`5.25 XX 10^6 m SEC^(-1)`

Discussion

49.	The approximate emf of a dry cell is :
Answer» `2.0 V` `1.2V` 6V `1.5`V Answer :D

Discussion

50.	The approximate density of CO_2 gas at STP is :
Answer» 1 mol/litre 2 g/litre 2 g/mL 44 g/Ml Answer :B

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

The arrangement ABC ABC….is referred to as

The aromatic compounds present as particulates are :

The aromatic compounds is present as particulates are

The aromatic compounds having formula C_(7)H_(8)O which are easily ientifiable by FeCl_(3) solution test (violet colouration) are

The Arrhenius equation expressing the effect of temperature on the rate constant of reaction is

The aqueous solutions of the following substances were electrolysed. In which case, the pH of the solution does not change if inert electrodes are used.

The aqueous solutions of sodium formate , anilinium chloride and potassium cyanide are respectively ………..

The aqueous solutions of sodium formate, anilinium chloride and potassium cyanide are respectively

The aqueous solutions of the following salts will be coloured in case of

The aqueous solutions, containing respectively 7.5 g of urea (mol. Wt = 60) and 42.75 g substance X in 100 g of water freeze at the same temperature. Calculate the molar mass of X.

The aqueous solution of which vitamin is darkpink in colour:

The aqueous solution of which one of the following is basic

The aqueous solution of urea has freezing point -0.6^(@)C. To prepare such solution how much gram of urea is needed to dissolve in 3 kg of water ? (M = 60 gm/mol) (K_(f)=1.5^(@)C" kg mol"^(-1)).

The aqueous solution of which of the following salt has the lowest pH

The aqueous solution of transition metal salt changes colour from pink to blue, when concentrated hydrochloric acid is added to it. The changes in colour is due to:

The aqueous solution of the following salts will be coloured in the case of

The aqueous solution of the following salt will be coloured in the case of :

The aqueous solution of sugar does not conduct electricity whereas when sodium chloride is added to water, it conducts electricity. Justify this statement.

The aqueous solution of sodium acetate with minimum pH is

The aqueous solution of sodium formate, anilinium chloride and potassium cyanide are respectively…..

The aqueous solution of salt gives white ppt with lead acetate solution which is insoluble in hot water and nitric acid. The salt contains

The aqueous solution of saltgives white ppt withlead aceetate solution whichis insolution inbut water and nitricacid .The salt contains

The aqueous solution of RCOOH contains,

The aqueous solution of following salt will have the lowestpH :

The aqueous solution of disodium hydrogen phosphate is :

The aqueous solution of each of the following salt is coloured except

The aqueous solution of CuSO_(4) is

The aqueoussolution of (C) on treatment with conc. H_(2)SO_(4) gives a orange coloured compound (E).

The aqueous solution of copper(II) sulphate is slowly hydrolysis forming basic copper sulphate whose chemical composition is:

The aqueous solution of an acid is characterised by the presence of :

The aqueous solution of aluminium chloride is acidic due to

The aqueous solution of aluminium chloride is acidic due to :

The aqueous solution of AlCl_(3) is acidic due to the hydrolysis of

The aqueous solution of a salt gives white ppt. with lead acetate solution which is insoluble in hot water and nitric acid . The salt contains :

The aqueous solution of a complex compound having the formula coBrCl_(2).4NH_(3)conducts electricity and also gives white precipitate with AgNO_(3). Write the IUPAC notation and IUPAC name of the compound.

The aqueous solution containing which one of the following ions will be colourless (Atomic number Sc=21, Fe=26, Ti=22, Mn=25)

The aqueous solution containing which one fo the following ions will be colourless ?

The approximate time duration in hours to electroplate 30 g of calcium from molten calcium chloride using a current of 5 amp is [At. Mass of Ca=40]

The aqeous solution of which of the following salt will have the lowest pH ?

The aqueous solution containing which one of the following ion will be colourless ?

The approximate time duration in hours to electroplate 30 g of calcium from molten calcium chloride using a current of 5 amp is [At., mass of Ca = 40]

The approximate percentage of iron in mischmetal is :

The approximate of benzene in 90%

The approximate mass of an electron is 10^(-27) g. Calculate the uncertainty in its velocity if the uncertainty in its position were of the order of 10^(-11) m

The approximate emf of a dry cell is :

The approximate density of CO_2 gas at STP is :