94420 + Interview Questions in Chemistry in Class 12

1.	If N_(0) is the initial number of nuclie , number of nuclei remaining undecayed at the end of nth half life is :
Answer» `2^(-N) N_(0)` `2^(n) N_(0)` `n^(-2) N_(0)` `n^(2) N_(0)` SOLUTION :`N_(t) = (N_(0))/(2^(n))`

Discussion

2.	If N_(0) and N are the number of radioactive particles at time t = 0 and t = t, then
Answer» `LAMDA = (1)/(t) "LOG" (N_(0))/(N)` `lamda = (2.303)/(t) "log"(N)/(N_(0))` `lamda = (t)/(2.303)"log"(N_(0))/(N)` `lamda = (2.303)/(t) "log" (N_(0))/(N)` Answer :D

Discussion

3.	If N^(0) is the initial number of nuclei, number of nuclei remaining undecayed at the end of n^(th) half-life is
Answer» `2^(-N) N^(0)` `2^(n) N^(0)` `n^(-2) N^(0)` `n^(2) N^(0)` ANSWER :A

Discussion

4.	If 'n' represents total number to asymmetric carbon atoms in a compound, the possible number of optical isomers of the compound is
Answer» 2n `N^(2)` `2^(n)` `2n+2` Solution :The POSSIBLE number of isomers of the compound is given by `2^(n)` where ',' represents TOTAL number of asymmetric carbon ATOMS in a compound.

Discussion

5.	If 'n' is the number of ions given by 1 mole of electrolyte, the degree of dissociation 'alpha' of electrolyte is -
Answer» `(i-1)/(n+1)` `(i-1)/(n-1)` `(n-1)/(i-1)` `(n+1)/(i-1)` ANSWER :B

Discussion

6.	If N and S elements are present in organic compound, then during Lassaigne's test both change into
Answer» `Na_(2)S " and NaCN` `NaSCN` `Na_(2)SO_(3) " and " Na_(2)CO_(3)` `Na_(2)S" and " NaCNO` Solution :SEE Lassaigne's test in UNIT 5.5.

Discussion

7.	If n and l are respectively the principal and azimuthal quantum numbers, then the expression for the calculation of the total no. of electrons in any energy level is
Answer» `sum_(l=0)^(l=n)2(2l+1)` `sum_(l=n+1)^(l=n-1)2(2l+1)` `sum_(l=0)^(l=n+1)2(2l+1)` `sum_(l=0)^(l=n-1)2(2l+1)` Solution :No. of sub-shells in `n^("th")` shell = 0 to n- 1. No of ORBITALS in a sub-shell = 2 l + l. No. of electrons in each orbital = 2. Hence no. of `E^(-)` in `n^("th")` shell `=sum_(l=0)^(l=n-1)2(2l+1)`

Discussion

8.	If n = 3, l= 0, m = 0, then atomic number is
Answer» 12 or 13 13 or 14 10 or 11 11 or 12 Solution :n = 3, l = 0 means last shell is 3s. `therefore` ELECTRONIC configuration will be `1s^(2)2s^(2)2P^(6)3s^(1-2)` ATOMIC number is 11 or 12.

Discussion

9.	If M,W and V represents molar mass of solute, mass of solute and volume of solution in litres respectively, which among following equations is true?
Answer» `pi = (MWR)/(TV)` `pi = (TMR)(WV)` `pi = (TMR)/(VM)` `pi = (TRV)/(WM)` Solution :ACCORDING to van'f Hoff solution equation `pi V = n RT` but `n = W/M` Hence `pi V = W/M RT` or `pi = (WRT)/(MV)`

Discussion

10.	If m_(p) is the mass of proton. m_(n) that of a neutron, M_(1) that of _(10)Ne^(20) nucleus and M_(2) that of _(20)Ca^(40) nucleus, then which of the following relations is//are not true?
Answer» `M_(2) gt 2M_(1)` `M_(2) lt 20 (m_(p)+m_(n))` `M_(2)=2M_(1)` `M_(2) lt 2M_(1)` Solution :More the nucleons, more the more the BINDING energy & more REDUCED is the mas. So, `M_(2) lt 20(m_(p)+m_(n))` (Because some mass got reduced on release of binding energy). `M_(2) lt 2M_(1)` (Because more mass is reduced for binding more nucleons)

Discussion

11.	If moving wih equal speed,the longest wavelength of the following matter waves is that for (an)
Answer» ELECRON `ALPHA`- kparticle PROTON Neutron Answer :A

Discussion

12.	If molecules is pyramidal, X stereoisomers are possible for : ""C_(abed) Find the value of X.
Answer» SOLUTION :x=6

Discussion

13.	If molecular weight of compound is increased then sensitivity is decreased in which of the following methods
Answer» Elevation in boiling point Viscosity OSMOSIS DIALYSIS Solution :According to the dialysis process molecular weight INCREASES but SENSITIVITY decreases.

Discussion

14.	If molecular interaction betweentwo different liquid molecules are stronger than the molecular interactions between the pure liquid molecules, the mixture is expected to show:
Answer» POSITIVE deviations NEGATIVE deviations No Deviations Positive as WELL as negative deviations Answer :B

Discussion

15.	If molecular axis is X then which of the following overlapping will form pi bond p_(z)+p_(z),p_(x)+p_(x),p_(x)+p_(y),p_(s)+p_(z),p_(y)+p_(y)
Answer»

Discussion

16.	If molarity = molality and density of the solution is 2gm/ml thenW_("solute"):W_("solvent") would be
Answer» `1:2` `2:1` `1:1` `1:3` Solution :`:.` Given that Molarity =molality `("moles")/(V(sdn)(L))=("moles")/(W("SOLVENT")(kg))` `IMPLIES W_(("solvent"))` is numerically EQUAL to volume of the solution. `V_(("so In"))=(W("solution"))/(d("solution"))implies(w("solution"))/(d("solution"))=W` (solvent) `((W_("solution"))/(W_("solvent"))-d_("solution"))` As `d=2` gm/ml `impliesW_("solution")=2W_("solvent")impliesW_("solute")=W_("solvent")`

Discussion

17.	If molar heat of vaporization is 9698 cals mol^(-1) then entropy of vaporization of water at 100^(@)C will be
Answer» 20.0 CALS `MOL^(-1) k^(-1)` 24.0 cals `mol^(-1) k^(-1)` 26.0 cals `mol^(-1) k^(-1)` 28.0 cals `mol^(-1) k^(-1)` ANSWER :C

Discussion

18.	If mole fraction of the solvent in a solution decreases then:
Answer» VAPOUR PRESSURE of SOLUTION increases B.pt. decreases Osmotic pressure increases All are correct Answer :C

Discussion

19.	IF molalityof thedilutesolutionisdoubledthe valueof molaldepressionconstant(K_(f))will be______.
Answer» Dobled halved tripled unchanged. Solution :VOLUE of `K_(f)` depends only UPON the natur of the SOLVENT. It is independent of the CONCENTRATION of the solution.

Discussion

20.	If molality of the dilute solution is doubled, the value of the molal depression constant (K_(f)) will be
Answer» doubled halved tripled unchanged Solution :MOLAL depression constant `(K_(F))` depends only on the solvent and is INDEPENDENT of the molality of the solution.

Discussion

21.	If mirror image of the compouns is not superimposable on it, most appropriately it represent
Answer» PAIR of OPTICAL ACTIVE isomers pair of structuralisomers pair of geometricalisomers pair of keto-enol tautomers Answer :A

Discussion

22.	If molality of the dilute solution is doubled, the value of molal depression constant (K_f) will be
Answer» unchanged doubled halved tripled Answer :A

Discussion

23.	If M_("normal") is the normal molecular mass and alpha is the degree of ionsation of K_(3)[Fe(CN)_(6)], then the abnormal molecular mass of the complex in the solution will be
Answer» `M_("NORMAL")(1+2alpha)^(-1)` `M_("normal")(1+3alpha)^(-1)` `M_("normal")(1+alpha)^(-1)` EQUAL to `M_("normal")` ANSWER :B

Discussion

24.	If Mg^(2+) +2e rarrMg(s), E=-2.37 V,Cu^(2+) + 2e rarrCu(s),E=+0.34V then theemf of the cell Mg\|Mg^(+2)\|\|Cu^(2+)\|Cu is :
Answer» `2.71V` `2.30V` `2.80V` `1.46V` ANSWER :A

Discussion

25.	If methyl group is on axial possition in product ( P-4),then what is the possition of Br-atoms on C_(1) "and"C_(2) respectively?
Answer» Axial-equatrial Equatorial-axial Axial-axial Equatorial-equatorial SOLUTION :

Discussion

26.	If methyl iodide and ethyl iodide are mixed in equal proportions, and the mixture is treated with metallic sodium in presence of dry ether, the number of possible products formed is:
Answer» 2 3 1 4 Answer :B

Discussion

27.	If methyl bromide and ethyl bromide are mixed in equal proportion and the mixture is treated with sodium, the number of possible organic products is :
Answer» 1 2 3 4 Solution :`{:((i) 2CH_(3)Br+2Na,rarrCH_(3)CH_(3),"(Ethane)"),((II)2CH_(3)CH_(2)Br+2Na,rarrC_(4)H_(10),"(Butane)"),((iii)CH_(3)Br+C_(2)H_(5)Br+2Na,rarrC_(3)H_(8),"(PROPANE)"):}`

Discussion

28.	If methyl bromide and ethyl bromide are mixed iequal proportion and themixture is treated with Na metal, the number of possible organic product are
Answer» 2 3 4 5 Solution :`3CH_(3)Br+6Na+3C_(2)H_(5)Br overset("dry ether") to C_(2)H_(6)C_(4)H_(10)+C_(3)H_(8)+6NaBr`

Discussion

29.	If metal ions of groups III are precipitated by NH_(4)Cl and NH_(4)OH without prior oxidation by conc. HNO_(3)....... is not completely precipitated.
Answer» ANSWER :`FE^(2+)`

Discussion

30.	If methanol vapour is passed over heated copper at 300^@C, it forms formaldehyde by:
Answer» Hydrogenation Dehydrogenation Dehydration Oxidation Answer :B

Discussion

31.	If mass % of oxygen in monovalent metal carbonate is 48% ,then find the number of atoms of metal present in 5mg of this metal carbonate sample is (N_(A) = 6.0 xx 10_(23) )
Answer» ANSWER :`6XX10^(19)`

Discussion

32.	If matel ionsof group II are precipitate by NH_(4)CI and NH_(4)OH without prior oxidationby conconirated HNO_(3) _____is not completelyprecipitate
Answer» Solution :If METAL IONS of groupIII areprecipitate by `NH_(4)CI` and `Nh_(4)OH`withoutprioroxidationby CONCENTRATED `HNO_(3)` FERRIC ion notcompletelyprecipitate .Nitric oxideoxidisesferrous to ferric ions

Discussion

33.	If mass of neutron is assumed to half of its original value. Whereas that of proton is assumed to be twice of its original value, then the atomic mass of ._(6)^(14C will be:
Answer» same 14.28% more 14.28% less 28.56% less Solution :In the ISOTOPE `._(6)^(14)C`: number of protons=6 Number of neutrons=8 New atomic MASS will be `=2xx6+(1)/(2)xx8=16` % Increase in mass `=(16-14)/(14)xx100=14.28%`.

Discussion

34.	If mercury is used as cathode in the electrolysis of aqueous NaCl solution, the ions dischaged at cathode are:
Answer» `H^+` `Na^+` `OH^-` `CI^-` ANSWER :B

Discussion

35.	If mass of KHC_(2)O_(4) (potassium acid oxalate) required to reduce 100 mL of 0.02 M KMnO_(4) in acidic medium is x g and to neutralise 100 mL of 0.05 M Ca(OH)_(2) is y g, then which of the following options may be correct :
Answer» If x is 1 g then y is 2 g If x is 5.5g then y is 11G If x is 2g then y is 1g If x is 11g then y is 5.5g Answer :A::B

Discussion

36.	If magnetic moment of [MnBr_(4)]^(2-) is 5.9 BM. Predict the number of electrons?
Answer» 2 3 6 5 Solution :MAGNETIC MOMENT can be calculated by using the relation `sqrt(n(n+2)B.M.)` where n=number of ELECTRONS and B.M. is Bohr MAGNETON. `therefore 5.9=sqrt(n(n+2))` `therefore n=5`.

Discussion

37.	If m represents mass of substance (equivalent weight E) consumed or produced when quantity Q of electricity is passed
Answer» `m PROP Q` `m prop 1//Q` `m prop 1//E` `m prop Q .E` SOLUTION :Combining Faradays 1ST and 2nd LAW.

Discussion

38.	If m is the mass of a substance with equivalent weight E and Q is quantity of electicity passed , then
Answer» `m PROP (1)/(Q)` `m prop Q.E` `m prop (1)/(E)` `m prop Q` ANSWER :B

Discussion

39.	If M is the element of actinoid series, the degree of complex formation decreases in the order
Answer» `M^(4+) GT M^(3+) gt MO_(2)^(2+) gt MO_(2)^(+)` `MO_(2)^(+) gt MO_(2)^(2+) gt M^(3+) gt M^(4+)` `M^(4+) gt MO_(2)^(+) gt M^(3+) gt MO_(2)^(+)` `MO_(2)^(3+) gt MO_(2)^(+) gt M^(4+) gt M^(3+)` ANSWER :B

Discussion

40.	If 'M' is a monovalent metal , the order of ionic character of their halides respectively is
Answer» `MFgtMClgtMBrgtMI` `MIgtMBrgtMClgtMF` `MFgtMClgtMIgtMBr` `MClgtMFgtMBrgtMI` ANSWER :A

Discussion

41.	If l=length, R=resistance and A=cross sectional area, then. . . .
Answer» `RPROP(l)/(A)` `Rprop(A)/(l)` `Rprop(l)/(Al)` `Rprop lA` SOLUTION :Resistance of any equal conductor is DIRECTLY PROPORTIONAL to its length and inversely proportional to its cross-sectional area (A). So, `Rprop(l)/(A)`.

Discussion

42.	If liquids A and B form an ideal solution,
Answer» the ENTROPY of mixing is zero the free energy of mixing is zero the free energy as WELL as the entropy of mixing are each zero the ENTHALPY of mixing is zero Answer :D

Discussion

43.	If Lamda_(NaOAc)^(@)=91 and Lamda_(HCl)^(@)=496.2" S "cm^(2)mol^(-1) then what is required to find out Lamda_(HOA c)^(@) ?
Answer» `Lamda_(ClCH_(2)COOH)` `Lamda_(CH_(3)COOH)` `lamda_(H+)^(@)` `Lamda_(NaCl)^(@)` Solution :`Lamda_(NaAc)^(@)=(Lamda_(NaAc)^(@)+Lamda_(HCl)^(@))-(Lamda_(NaCl)^(@))` i.e., by KNOWING the value of `^^_(NaCl)^(@)`, we can DETERMINE `^^_(HOA C)^(@)`.

Discussion

44.	If lamdaClCH_(2)COONa=224Ohm^(-1)cm^(2)gm" "equ^(-1),lamdaNaCl=38.2Ohm^(-1)cm^(2)" gm "equ^(-1) and lamdaHCl=203Ohm^(-1)cm^(2)" gm "equ^(-1), then what is the value of lamdaClCH_(2)COOH ?
Answer» `288.5Ohm^(-1)cm^(2)" gm "EQU^(-1)` `289.5Ohm^(-1)cm^(2)" gm "equ^(-1)` `388.5Ohm^(-1)cm^(2)" gm "equ^(-1)` `59.5Ohm^(-1)cm^(2)" gm "equ^(-1)` SOLUTION :`lamdaClCH_(2)COOH` `=lamdaClCH_(2)COONa+lamdaHCl-lamdaNaCl` `=224+203-38.2` `=388.8Ohm^(-1)cm^(2)" gm "equ^(-1)`.

Discussion

45.	If Lamda^(@)CH_(3)COONa=91" S "cm^(2)mol^(-1)," "Lamda^(@)HCl=462.2" S "cm^(2)mol^(-1), then choose correct option to determine Lamda^(@)CH_(3)COOH.
Answer» `lamda^(@)CL^(-)` `Lamda^(@)NaCl` `Lamda^(@)H^(+)` `Lamda^(@)ClCH_(2)COOH` SOLUTION :`Lamda^(@)NaCl`

Discussion

46.	If lamda=c_(2)[(n^(2))/(n^(2)-Z^(2))] for Balmer series what is the value of C_(2)?
Answer» `r/(R_(H))` `2/(R_(H))` `2R_(H)` `4R_(H)` Solution :`LAMDA=C_(2)[(N^(2))/(n^(2)-Z^(2))]implies1/(lamda)=1/(C_(2))[(n^(2)-Z^(2))/(n^(2))]` `implies1/(lamda)=1/(C_(2))[1-(Z^(2))/(n^(2))]` `=(Z^(2))/(C_(2))[1/(Z^(2))-1/(n^(2))]` `:.R_(Y)=(Z^(2))/(C_(2))impliesC_(2)=4/(R_(H))` Hence a is the correct answer.

Discussion

47.	If lambda_(0) is the threshold wavelnegth of a metal and lambda is the wavelength of the incident radiation, the maximum velocity of the ejected electron from the metal would be
Answer» `[ ( 2hc)/( m )((lambda_(0) - LAMBDA)/( lambda_(0) lambda))]^(1//2)` `[ ( 2hc)/( m )((lambda-lambda_(0) )/( lambdalambda_(0)))]^(1//2` `[ ( 2hc)/( m ) ( lambda - lambda_(0) ) ]^(1//2)` `[ ( 2hc)/( m ) ( lambda_(0) - lambda) ]^(1//2)` ANSWER :A

Discussion

48.	IfK_(sp)of M(OH)_(3) is 1 xx 10^(-12) then 0.001 M.M^(2+) isprecipitate in a pH gt 9
Answer» Solution :`M(OH)_(3) `is PRECIPITATE `[M^(3+)][OH^(Theta)]^(3) gt K_(sp) [OH^(Theta)]^(3)gt 1 XX 10^(-9)` `[OH^(Theta)] gt 1 xx 10^(-3)` Maximum `pOH = 3` Minimum `pH = 9` Hence true.

Discussion

49.	If lactobacillus bacteria (which converts milk to curd) multiply in milk as per the data given {:("Time(minute)",,0,,15,,45,,75),("No . of bacteria",,100,,200,,800,,3200):} 100g milk to curd requires 4xx10^(9) such bacteria. Atleast how many hours it will require to convert 1kg milk if initially 100 bacteria were mixed in it.
Answer» ANSWER :`8HRS`

Discussion

50.	If K_sp of HgSO_4, is 6.4 x 10^-5 M^2, then solubility of the HgSO_4, in water will be
Answer» `5.410^-5 M` `810^-3 M` `8* 10^-4 M` `6.4* 10^-3 M` ANSWER :B

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

If N_(0) is the initial number of nuclie , number of nuclei remaining undecayed at the end of nth half life is :

If N_(0) and N are the number of radioactive particles at time t = 0 and t = t, then

If N^(0) is the initial number of nuclei, number of nuclei remaining undecayed at the end of n^(th) half-life is

If 'n' represents total number to asymmetric carbon atoms in a compound, the possible number of optical isomers of the compound is

If 'n' is the number of ions given by 1 mole of electrolyte, the degree of dissociation 'alpha' of electrolyte is -

If N and S elements are present in organic compound, then during Lassaigne's test both change into

If n and l are respectively the principal and azimuthal quantum numbers, then the expression for the calculation of the total no. of electrons in any energy level is

If n = 3, l= 0, m = 0, then atomic number is

If M,W and V represents molar mass of solute, mass of solute and volume of solution in litres respectively, which among following equations is true?

If m_(p) is the mass of proton. m_(n) that of a neutron, M_(1) that of _(10)Ne^(20) nucleus and M_(2) that of _(20)Ca^(40) nucleus, then which of the following relations is//are not true?

If moving wih equal speed,the longest wavelength of the following matter waves is that for (an)

If molecules is pyramidal, X stereoisomers are possible for : ""C_(abed) Find the value of X.

If molecular weight of compound is increased then sensitivity is decreased in which of the following methods

If molecular interaction betweentwo different liquid molecules are stronger than the molecular interactions between the pure liquid molecules, the mixture is expected to show:

If molecular axis is X then which of the following overlapping will form pi bond p_(z)+p_(z),p_(x)+p_(x),p_(x)+p_(y),p_(s)+p_(z),p_(y)+p_(y)

If molarity = molality and density of the solution is 2gm/ml thenW_("solute"):W_("solvent") would be

If molar heat of vaporization is 9698 cals mol^(-1) then entropy of vaporization of water at 100^(@)C will be

If mole fraction of the solvent in a solution decreases then:

IF molalityof thedilutesolutionisdoubledthe valueof molaldepressionconstant(K_(f))will be______.

If molality of the dilute solution is doubled, the value of the molal depression constant (K_(f)) will be

If mirror image of the compouns is not superimposable on it, most appropriately it represent

If molality of the dilute solution is doubled, the value of molal depression constant (K_f) will be

If M_("normal") is the normal molecular mass and alpha is the degree of ionsation of K_(3)[Fe(CN)_(6)], then the abnormal molecular mass of the complex in the solution will be

If Mg^(2+) +2e rarrMg(s), E=-2.37 V,Cu^(2+) + 2e rarrCu(s),E=+0.34V then theemf of the cell Mg|Mg^(+2)||Cu^(2+)|Cu is :

If methyl group is on axial possition in product ( P-4),then what is the possition of Br-atoms on C_(1) "and"C_(2) respectively?

If methyl iodide and ethyl iodide are mixed in equal proportions, and the mixture is treated with metallic sodium in presence of dry ether, the number of possible products formed is:

If methyl bromide and ethyl bromide are mixed in equal proportion and the mixture is treated with sodium, the number of possible organic products is :

If methyl bromide and ethyl bromide are mixed iequal proportion and themixture is treated with Na metal, the number of possible organic product are

If metal ions of groups III are precipitated by NH_(4)Cl and NH_(4)OH without prior oxidation by conc. HNO_(3)....... is not completely precipitated.

If methanol vapour is passed over heated copper at 300^@C, it forms formaldehyde by:

If mass % of oxygen in monovalent metal carbonate is 48% ,then find the number of atoms of metal present in 5mg of this metal carbonate sample is (N_(A) = 6.0 xx 10_(23) )

If matel ionsof group II are precipitate by NH_(4)CI and NH_(4)OH without prior oxidationby conconirated HNO_(3) _____is not completelyprecipitate

If mass of neutron is assumed to half of its original value. Whereas that of proton is assumed to be twice of its original value, then the atomic mass of ._(6)^(14C will be:

If mercury is used as cathode in the electrolysis of aqueous NaCl solution, the ions dischaged at cathode are:

If mass of KHC_(2)O_(4) (potassium acid oxalate) required to reduce 100 mL of 0.02 M KMnO_(4) in acidic medium is x g and to neutralise 100 mL of 0.05 M Ca(OH)_(2) is y g, then which of the following options may be correct :

If magnetic moment of [MnBr_(4)]^(2-) is 5.9 BM. Predict the number of electrons?

If m represents mass of substance (equivalent weight E) consumed or produced when quantity Q of electricity is passed

If m is the mass of a substance with equivalent weight E and Q is quantity of electicity passed , then

If M is the element of actinoid series, the degree of complex formation decreases in the order

If 'M' is a monovalent metal , the order of ionic character of their halides respectively is

If l=length, R=resistance and A=cross sectional area, then. . . .

If liquids A and B form an ideal solution,

If Lamda_(NaOAc)^(@)=91 and Lamda_(HCl)^(@)=496.2" S "cm^(2)mol^(-1) then what is required to find out Lamda_(HOA c)^(@) ?

If lamdaClCH_(2)COONa=224Ohm^(-1)cm^(2)gm" "equ^(-1),lamdaNaCl=38.2Ohm^(-1)cm^(2)" gm "equ^(-1) and lamdaHCl=203Ohm^(-1)cm^(2)" gm "equ^(-1), then what is the value of lamdaClCH_(2)COOH ?

If Lamda^(@)CH_(3)COONa=91" S "cm^(2)mol^(-1)," "Lamda^(@)HCl=462.2" S "cm^(2)mol^(-1), then choose correct option to determine Lamda^(@)CH_(3)COOH.

If lamda=c_(2)[(n^(2))/(n^(2)-Z^(2))] for Balmer series what is the value of C_(2)?

If lambda_(0) is the threshold wavelnegth of a metal and lambda is the wavelength of the incident radiation, the maximum velocity of the ejected electron from the metal would be

IfK_(sp)of M(OH)_(3) is 1 xx 10^(-12) then 0.001 M.M^(2+) isprecipitate in a pH gt 9

If K_sp of HgSO_4, is 6.4 x 10^-5 M^2, then solubility of the HgSO_4, in water will be