94420 + Interview Questions in Chemistry in Class 12

1.	Four flask of 1 litre capacity each are separately filled with gasesH_2,He,O_2 and O_3. At the same temperature and pressure, the ratio of the number of atoms of these gases present in different flask would be :
Answer» 1:1:1:1 2:1:2:3 1:2:1:3 3:2:2:1 Solution :`H_(2):He:O_(2):O_(3)=2:1:2:3`.

Discussion

2.	Four equations are given below. Decide if they are correctly balanced or not. (T for true and F for false) (i) M_(x)O_(y) + YC to x M + YCO (ii) 2Al_2O_3 + 3C to 4Al + 3CO_2 (iii) FeO + SiO_2 to FeSiO_3 (iv) Cu_2S + 2Cu_2O to 6Cu + SO_2
Answer» T T T T T T T F T F T F T T F T Answer :A

Discussion

3.	Four elements A, B ,C and D have standard oxidation potential values as : 2.87V , +2.71V, 1.67V and -2.87V. The strongest reducing agent will be
Answer» A B C D Solution :Smallest VALUE of `E_("red")^(0)` of ZN - strongest reducing AGENT.

Discussion

4.	Four complexes are given : (P) [CoCl(NH_(3))_(5)]^(2+)""(Q) [Co(NH_(3))_(5)(H_(2)O)]^(3+) (R ) [Co(NH_(3))_(6)]^(3+)""(S) [Co(CN)_(6)]^(3-) All of them exhibit at least one of the following 4 colours viz, violet, red, yellow orange, pale yellow. One of them absorbs light in the U.V. region. Choose the correct statement(s).
Answer» Order of wavelength of light absorbed : `PgtQgtRgtS` S must be violet in COLOUR R must have absorbed wavelength of blue colour light Q must be pale YELLOW in colour Solution :Order of `Delta_(0) : (S) gt (R ) gt (Q) gt (P), Delta_(0) prop(1)/(lambda_(ABS))`

Discussion

5.	Four containers of 2L capacity contains dinitrogen as described below. Which one contains maximum number of molecules?
Answer» `25` G-molecule of `N_(2)` 4 g-atom of nitrogen `301xx10^(24)` N atoms 82 g of dinitrogen Solution :82 g of `N_(2) = (84)/(28)` gm-molecule `= 2*92` moles

Discussion

6.	Four colourless salt solutions are placed in separate test tubes and a strip of copper is placed in each. Which solution finally turns blue:
Answer» `Pb(NO_3)_2` `ZN(NO_3)_2` `AgNO_3` `CD(NO_3)_2` ANSWER :C

Discussion

7.	Four colourless salt solutions are placed in separate test tubes and a strip of copper is placed ineach. Which solution finally turns blue?
Answer» `PB(NO_3)_2` `AgNO_3` `Zn(NO_3)_2` `Cd(NO_3)_2` SOLUTION :`Zn^(+2)//Zn(0.762) ,Cd^(=2) // Cd ` ` Pb^(+2)//Pb , Cu^(+2)//Cu` `Ag^(+)//Ag , m + 2AgNO_3 to Cu(NO_3)_2 + 2AG^(OPLUS)`

Discussion

8.	Four colourless salt solutions are placed in separate test-tubes and a strip of copper is placed in each . Which solution finally turns blue
Answer» `CD(NO_(3))_(2)` `ZN(NO_(3))_(2)` `AgNO_(3)` `Pb(NO_(3))_(2)` ANSWER :C

Discussion

9.	Foul smell in the water of tanks, ponds etc. is due to
Answer» Anaerobiosis Acrobiosis Biological magnification Psammophytes Answer :A

Discussion

10.	Fot the reaction A + B to produts, it is found that orders of the reaction in A and B are 1 and 2 respectively. When the conc. ofA is halved and that of B is doubled, the rate increases by a factor :
Answer» 2 8 4 16 Solution :For the reaction, `A +B to` PRODUCTS,the rate law is `(dx)/(dt)=r_1=k[A][B]^2`… (i) `r_2 = k[1/2][2B]^2`…(ii) `or r_2= 1/2xx2^2k[A][B]^2`…(iii) Dividing (iii) by (i) `(r_(2))/(r_(1)) = (2 k [A][B]^(2))/(k[A][B]^(2)) = 2 therefore r_(2) = 2r_(1)`

Discussion

11.	Four alkali metals A,B,C and D are having respectively standard electrode potential as -3.05, -1.66, -0.40 and 0.80. Which one will be the most reactive.
Answer» A B C D Solution :More NEGATIVE is the STANDARD reduction potential, greater is the TENDENCY to lose electrons and HENCE greater REACTIVITY.

Discussion

12.	Fortbcclcctrochcmical cell, M \|M^(+)\|\|X^(-)\|X,E ^(@)_(M^(4)//M)=0.44and E ^(@)_(X//X)=0.33V. From this data one can deduce that
Answer» `M +Xto M ^(+)+X` is the SPONTANEOUS REACTION `M ^(+)+X to M +X` is the spontaneous reaction `E_(CELL")=0.77V` `E_(cell)=0.77V` Solution :For,` M^(+)+X^(-) to M+X, E+_(cell)^(@)=0.44 -0.33=0.11V` is positive, hence reaction is spontaneous.

Discussion

13.	Formulate the galvanic cell in which the following reaction takes place: Zn(s)+2Ag^(+)(aq)toZn^(2+)(aq)+2Ag(s) State (i) Which one of the electrodes is negatively charged? (ii) The reaction taking place at each of its electrode. ltBrgt (iii) The carriers of current within this cell.
Answer» Solution :The cell reaction is : `Zn(s)+2AG^(+)(aq)TOZN^(2+)(aq)+2Ag(s)` The cell is represented as: `Az(s)\|Zn^(2+)(aq)\|\|Ag^(+)(aq)+Ag(s)` (i) ANODE i.e., zinc electrode is negatively charged. (ii) At anode: `Zn(s)toZn^(2+)(aq)+2e^(-)` At cathode: `Ag^(+)(aq)+e^(-)toAg(s)` (III) Within the cell, the current is carried by the cations and the anions through the salt bridge. In the external circuit, electrons FLOW from zinc to silver andhence conventional current flows from silver to zinc.

Discussion

14.	Formulate the compound tetraammineaquachloridocobalt (III) chloride
Answer» Solution :Anion (simple ion) `=Cl^(-)` for the COORDINATION ENTITY, writing FIRST the symbol for metal atom and then the ligands in the alphabetical order, we have Cation (complex ion) `=[Co(NH_(3))_(4)(H_(2)O)Cl]^(x)` where x is the charge on the complex ion. x = oxidation state to cobalt + charge on the ligands x=+3+0+0+(-1)=+2 (`H_(2)O` and `NH_(3)` are neutral group and carry no charge. Only chlorido group carries charge = - 1) Charge on one anion = - 1 Charge on complex cation = + 2 Clearly, two anions will NEUTRALISE the charge of the cation. Hence, formula of the given compound is `[Co(NH_(3))_(4)(H_(2)O)Cl]Cl_(2)`.

Discussion

15.	Formulae for ortho-, pyro-, chain-, and double chain silicates are respectively:
Answer» `[SiO_(4)]^(4-), [Si_2O_7]^(6-),[Si_2O_3]^(2-),[SiO_11]^(6-)` `[SiO_(4)]^(4-), [Si_2O_7]^(6-),[SiO_3]^(2-),[Si_(4)O_11]^(6-)` `[SiO_(4)]^(4-), [S_2iO_7]^(4-),[SiO_3]^(2-),[SiO_11]^(6-)` `[SiO_(4)]^(4-), [Si_2O_6]^(6-),[SiO_3]^(2-),[SiO_11]^(6-)` SOLUTION :`{:("Orthosilicate",-,"No oxygen is shared" ,SiO_(4)^(4-)),("Pyrosilicate",-,"Only one oxygen is shared",SiO_(7)^(6-)),("Chain silicate",-,"Two oxygen are shared",SiO_(3)^(2-)),("Chain silicate", -,"Two oxygen are shared",SiO_(3)^(2-)):}`

Discussion

16.	Formula of tris(ethane-1,2-diamine)iron(II)phosphate
Answer» `[FE(CH_(3)-CH(NH_(2))_(2))_(3)](PO_(4))_(3)` `[Fe(H_(2)N-CH_(2)-CH_(2)-NH_(2))_(3)](PO_(4))` `[Fe(H_(2)N-CH_(2)-CH_(2)-NH_(2))_(3)](PO_(4))_(2)` `[Fe(H_(2)N-CH_(2)-CH_(2)-NH_(2))_(3)](PO_(4))_(2)` Solution :`[Fe(H_(2)N-CH_(2)-CH_(2)-NH_(2))_(3)](PO_(4))_(2)`

Discussion

17.	Formula of thiosulphate, manganate and arsenate respectively are
Answer» `S_(4)O_(6)^(2-),MnO_(4)^(2-),AsO_(3)^(3-)` `S_(2)O_(3)^(2-),MnO_(4)^(2-),AsO_(4)^(3-)` `S_(2)O_(3)^(2-),MnO_(4)^(2-),AsO_(3)^(3-)` `S_(4)O_(6)^(2-),MnO_(4)^(2-),AsO_(4)^(3-)` Answer :D

Discussion

18.	Formula of the compound in which the element Y forms CCP lattice and atoms of Xoccupy 1/3rd of THV :-
Answer» `XY_3` `X_3Y` `X_2Y_3` `X_3Y_2` Solution :Y `to` CCP = 4 `X to 8 xx 1/3=8/3` `X_2Y_3`

Discussion

19.	Formula of tris (ethane 1,2-diamine ) iron (II) phosphate
Answer» ` [FE(CH_3-CH(NH_2)_2)_3 (PO_4) _3` ` [Fe(H_2N-CH_2CH_2-NH_2 )_3](PO_4) ` ` [Fe (H_2N-CH_2-CH_2-NH_2)_3] (PO_4) _2` ` [Fe (H_2 N-CH_2 -CH_2 -NH_2) _3 ]_3 (PO_4) _2` ANSWER :D

Discussion

20.	Formula of Silicate is ?
Answer» `Si_6O_20^(-12)` `Si_6O_18^(-4)` `Si_6O_18^(-12)` `Si_8O_19^(-12)` SOLUTION :

Discussion

21.	Formula of Rust is :
Answer» `Fe_(2)O_(3)` `FEOxH_(2)O` `Fe_(2)O_(3)xH_(2)O` `Fe_(3)O_(4)*xH_(2)O` Answer :C

Discussion

22.	Formula of rhombic sulphur is
Answer» `S_2` S `S_4` `S_8` ANSWER :D

Discussion

23.	Formula of peroxodisulphuric acid(Marshall"s acid) is
Answer» `H_2SO_5` `H_2S_2O_5` `H_2S_2O_7` `H_2S_2O_8` ANSWER :D

Discussion

24.	Formula of nylon -66 is
Answer» `[OC(CH_2)_6CONH(CH_2)_4NH]_n` `[OC(CH_2)_4CONH(CH_2)_6NH]_n` `[OC(CH_2)_4CONH(CH_2)_4NH]_n` `[OC(CH_2)_6CONH(CH_2)_6NH]_n` ANSWER :B

Discussion

25.	Formula of phosphorus triiodide is:
Answer» `PI_3` `I_2(PO_4)_3` `IPO_4` `I_2PO_4` ANSWER :C

Discussion

26.	Formula of Hexamethylenediamine is _____.
Answer» SOLUTION :`NH_2 \\ (-CH_2)_6-NH_2`

Discussion

27.	Formula of hexa-aquamangnnese (II) phosphate is
Answer» `[MN(H_(2)O)_(6)][PO_(4))` `[Mn(H_(2)O)_(6)]_(3)(PO_(4))` `[Mn(H_(2)O)_(6)]_(3)(PO_(4))_(2)` `[Mn(H_(2)O)_(6)](PO_(4))_(3)` Solution :`[Mn(H_(2)O)_(6)]^(2+) PO_(4)^(3-)-=[Mn(H_(2)O)_(6)]_(3)(PO_(4))_(2)`

Discussion

28.	Formula of hexaaquamanganese (II) phosphate is
Answer» `[Mn(H_(2)O)_(6)](PO_(4))` `[Mn(H_(2)O)_(6)]_(3)(PO_(4))` `[Mn(H_(2)O)_(6)]_(3)(PO_(4))_(2)` `[Mn(H_(2)O)_(6)](PO_(4))_(3)` ANSWER :C

Discussion

29.	Formula of ferrocene is :
Answer» `[Fe(CN)_(4)]^(4-)` `[Fe(CN)_(6)]^(3+)` `[Fe(CO)_(5)]` `[Fe(C_(5)H_(5))_(2)]` Answer :D

Discussion

30.	Formula of Feldspar is
Answer» `K_(2) O. Al_(2)O_(3). 6 SiO_(2)` `K_(2) O. Al_(2)O_(3). 6 Si_(2). O_(2). 2H_(2)O` `Al_(2) O_(3). 2SiO_(2). 2H_(2)O` `3MgO.4 SiO_(2). H_(2)O` Solution :Felspar is `K_(2)O.Al_(2)O_(3).6SiO_(2)`

Discussion

31.	Formula of diacetone alcohol is:
Answer» `(CH_2)C(OH)CH_2COCH_2` `CH_2CHOHCH_2COCH_2` `(CH_3)_2C(OH)CH_2COCH_3` None Answer :A

Discussion

32.	Formula of calcium chlorite is:
Answer» `CaClO_ 2` `CA(ClO_2)_2` `Ca(ClO_3)_2` `Ca(ClO_4)_2` ANSWER :B

Discussion

33.	Formonitrile is reduced by SnCl_(2) + HCl and product on acid hydrolysis gives
Answer» FORMIC ACID methanal acetic acid acetone Answer :B

Discussion

34.	Formula for phosgene is ____________
Answer» `COCl_(2)` `CaOCl_(2)` `CaCO_(3)` COCL Answer :A

Discussion

35.	Formic and acetic acid may be distinguished by the reaction with
Answer» SODIUM METAL Tollen's REAGENT sodium ethoxide NaOH ANSWER :B

Discussion

36.	Formic and acetic acid can be distinguished by
Answer» With AMMONIACAL `AgNO_3` With caustic SODA With SODIUM BICARBONATE With the help of litmus Answer :A

Discussion

37.	Formic acid reduces_____but acetic acid does not.
Answer» SOLUTION :TOLLENS' REAGENT or FEHLING's solution.

Discussion

38.	Formic acid reduces Tollen's reagent, but acetic acid does not-Give reasons.
Answer» Solution :(i) Formic acid (HCOOH) is unique because it contains both an aldehyde group and carboxyl group also. (ii) Hence it can act as a reducing agent. It REDUCES Fehling's solution Tollen's reagent and decolourises pink coloured `KMnO_(4)` solution. (iii) Whereas in acetic acid, there is no aldehyde group and it cannot act as reducing agent. (iv) Formic acid reduces ammoniacal SILVER nitrate solution (Tollen's reagent) to metallic silver. `HCOOH+Ag_(2)OtoH_(2)O+CO_(2)+2Agdarr` (metallic silver) (v) Formic acid reduces Fehling's solution. It reduces BLUE coloured cupric ions to red coloured cuprous ions. `HCOO^(-)+underset("(blue)")(2CU^(2+))+5OH^(-)toCO_(3)^(2-)+underset("(red)")(Cu_(2)O)+3H_(2)O`

Discussion

39.	Formic acid reduces ammoniacal AgNO_3 solution and Fehling.s solutionbecause:
Answer» All organic acids do so Formic ACID has ALDEHYDE like structure Formic acid is an aliphatic acid None of the above STATEMENT is correct Answer :B

Discussion

40.	Formic acid owes its origin to
Answer» MILK butter red ants vinegar ANSWER :C

Discussion

41.	Formic acid reacts with conc . H_(2)SO_(4) to give :
Answer» OXALIC acid Formaldehyde CO `CO_(2)` SOLUTION :`HCOOHoverset(Conc.H_(2)SO_(4))toCO+H_(2)O`

Discussion

42.	Formic acid is obtained when :
Answer» CALCIUM formate is heated with calcium acetate calcium acetate is heated with CONC .`H_(2)SO_(4)` ACELALDEHYDE is oxidised with `K_(2)Cr_(2)O_(7)andH_(2)SO_(4)` glycerol is heated with oxalic acid at 383K. Answer :D

Discussion

43.	Formic acid is more stronger than acetic acid. Justify this statement.
Answer» Solution :The ELECTRON releasing groups (+I groups) increase the relative charge on the carboxylate ion and destabilise it and hence the LOSS of proton BECOMES difficult. + I groups are `CH_3 - C_2H_5, - C_3H_7` `underset("FORMIC acid")(H-oversetunderset(\|\|)(O)(C ) -OH) gt underset("acetic acid ")(CH_3 - oversetunderset(\|\|)(O)(C ) -OH ) gt underset("propionic acid")(CH_3 - CH_2 - COOH) `

Discussion

44.	Formic acid is obtained when:
Answer» `(CH_3COO)_2Ca` is HEATED with conc.`H_2SO_4` CALCIUM formate is heated with calcium acetate Glycerol is heated with oxalic acid Acetaldehyde is oxidised with `K_2Cr_2O_7` and conc.`H_2SO_4` Answer :C

Discussion

45.	Formic acid is not a representative member of the carboxylic acids because :
Answer» It is the first member of the series It does not CONTAIN alkyl GROUP It is a gas It contains an ALDEHYDIC group while the other acids do not have the aldehydic group Answer :D

Discussion

46.	Formic acid is manufactured on large scale by treating X with sodium hydroxide under a pressure of a 1 atm and 473 K. X is ,
Answer» `CH_(3)OH` `CH_(4)` CO `H_(2)O` Answer :C

Discussion

47.	Formic acid is a stronger acid than acetic acid . This is due to the fact that
Answer» formic acid is reducing AGENT formic acid molecule is of smaller size there is no alkyl group on `ALPHA`- carbon in formicacid formic acid does not UNDERGO association Solution :ELECTRON donating alkyl GROUPS decrease the strength of acid. That is why formic acid is strongest acid than acetic acid.

Discussion

48.	Formic acid is a stronger acid than acetic acid.This can be explained using
Answer» `+M EFFECT` `-I effect` `+I effect` `-M effect` Solution :Formic acid is stronger acid than acetic acid. This can be EXPLAINED using+I effect. Acetic acid showing+I effect decreases the acid STENGTH as it increases the -ve charge on the carboxylate ion which HOLDS the hydrogen FIRMLY.

Discussion

49.	Formic acid is 4.6% dissociated in a 0.1 N solution at 20^@C . The ionisation constant of formic acid is :
Answer» `21xx10^(-4)` 21 `0.21xx10^(-4)` `2.1xx10^(-4)` ANSWER :D

Discussion

50.	Formic acid is a dibasic acid in nature: hence, it forms:
Answer» CO `CO_(2)` `C_(3)O_(2)` `SO_(2)` Solution :`HCOOH UNDERSET(-H_(2)O)OVERSET(H_(2)SO_(4))to CO`

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Four flask of 1 litre capacity each are separately filled with gasesH_2,He,O_2 and O_3. At the same temperature and pressure, the ratio of the number of atoms of these gases present in different flask would be :

Four equations are given below. Decide if they are correctly balanced or not. (T for true and F for false) (i) M_(x)O_(y) + YC to x M + YCO (ii) 2Al_2O_3 + 3C to 4Al + 3CO_2 (iii) FeO + SiO_2 to FeSiO_3 (iv) Cu_2S + 2Cu_2O to 6Cu + SO_2

Four elements A, B ,C and D have standard oxidation potential values as : 2.87V , +2.71V, 1.67V and -2.87V. The strongest reducing agent will be

Four containers of 2L capacity contains dinitrogen as described below. Which one contains maximum number of molecules?

Four colourless salt solutions are placed in separate test tubes and a strip of copper is placed in each. Which solution finally turns blue:

Four colourless salt solutions are placed in separate test tubes and a strip of copper is placed ineach. Which solution finally turns blue?

Four colourless salt solutions are placed in separate test-tubes and a strip of copper is placed in each . Which solution finally turns blue

Foul smell in the water of tanks, ponds etc. is due to

Fot the reaction A + B to produts, it is found that orders of the reaction in A and B are 1 and 2 respectively. When the conc. ofA is halved and that of B is doubled, the rate increases by a factor :

Four alkali metals A,B,C and D are having respectively standard electrode potential as -3.05, -1.66, -0.40 and 0.80. Which one will be the most reactive.

Fortbcclcctrochcmical cell, M |M^(+)||X^(-)|X,E ^(@)_(M^(4)//M)=0.44and E ^(@)_(X//X)=0.33V. From this data one can deduce that

Formulate the galvanic cell in which the following reaction takes place: Zn(s)+2Ag^(+)(aq)toZn^(2+)(aq)+2Ag(s) State (i) Which one of the electrodes is negatively charged? (ii) The reaction taking place at each of its electrode. ltBrgt (iii) The carriers of current within this cell.

Formulate the compound tetraammineaquachloridocobalt (III) chloride

Formulae for ortho-, pyro-, chain-, and double chain silicates are respectively:

Formula of tris(ethane-1,2-diamine)iron(II)phosphate

Formula of thiosulphate, manganate and arsenate respectively are

Formula of the compound in which the element Y forms CCP lattice and atoms of Xoccupy 1/3rd of THV :-

Formula of tris (ethane 1,2-diamine ) iron (II) phosphate

Formula of Silicate is ?

Formula of Rust is :

Formula of rhombic sulphur is

Formula of peroxodisulphuric acid(Marshall"s acid) is

Formula of nylon -66 is

Formula of phosphorus triiodide is:

Formula of Hexamethylenediamine is _____.

Formula of hexa-aquamangnnese (II) phosphate is

Formula of hexaaquamanganese (II) phosphate is

Formula of ferrocene is :

Formula of Feldspar is

Formula of diacetone alcohol is:

Formula of calcium chlorite is:

Formonitrile is reduced by SnCl_(2) + HCl and product on acid hydrolysis gives

Formula for phosgene is ____________

Formic and acetic acid may be distinguished by the reaction with

Formic and acetic acid can be distinguished by

Formic acid reduces_____but acetic acid does not.

Formic acid reduces Tollen's reagent, but acetic acid does not-Give reasons.

Formic acid reduces ammoniacal AgNO_3 solution and Fehling.s solutionbecause:

Formic acid owes its origin to

Formic acid reacts with conc . H_(2)SO_(4) to give :

Formic acid is obtained when :

Formic acid is more stronger than acetic acid. Justify this statement.

Formic acid is obtained when:

Formic acid is not a representative member of the carboxylic acids because :

Formic acid is manufactured on large scale by treating X with sodium hydroxide under a pressure of a 1 atm and 473 K. X is ,

Formic acid is a stronger acid than acetic acid . This is due to the fact that

Formic acid is a stronger acid than acetic acid.This can be explained using

Formic acid is 4.6% dissociated in a 0.1 N solution at 20^@C . The ionisation constant of formic acid is :

Formic acid is a dibasic acid in nature: hence, it forms: