94420 + Interview Questions in Chemistry in Class 12

1.	Gibbs free energy G , enthalpy H and entropy S are interrelated as in
Answer» G = H + TS G= H - TS G- TS- H G= S=H Solution :Gibbs free ENERGY `G_(1)` , ENTHALPY H and entropy S are isterrelated as G=H-TS

Discussion

2.	Fructose is ketose sugar even then it gives red precipitate with Fehling solution because :
Answer» Ketones are oxidised by Fehling solution Keto sugars undrego TRANSFORMATION into aldose sugars in the presence of Felhing's solution (1) and (2) both are CORRECT Both (1) and (2) incorrect Answer :D

Discussion

3.	Gibbs energy of formation triangleG_(f)^(G) of MgO (s) and CO (g) at 1273 K and 2273 K are given below : triangleG_f[MgO (s)]= -941"kJ mol"^(-1)" at 1273 K" triangleG_f [CO (g)]=-439"kJ mol"^(-1)" at 1273 K" triangleG_f [MgO (s)] =-314"kJ mol"^(-1)" at 2273 K" triangleG_f[CO (g)] =-628"kJ mol"^(-1)" at 2273 K" On the basis of above data, predict the temperature at which carbon can be used as a reducing agent for MgO (s).
Answer» Solution :For the reaction, `MgO(s)+C(s) to Mg(s)+CO(g)` At 1273 K, `triangleG_(r)=triangleG_(r) [CO(g)]-triangleG_(f) [MgO(s)]=-439-(-941)"kJ mol"^(-1)=502"kJ mol"^(-1)`. At 2273 K, `triangleG_(r)=-628-(-314)kJ mol^(-1)=-314"kJ mol"^(-1)`. The TEMPERATURE is 2273 K.

Discussion

4.	Fructose has a specific rotation -92.4^(@). An aqueous solution of Fructose has an observed rotation of -27.7^(@), when placed in a polarimeter tube of 10 cm long. How much amount of Fructose is dissolved in 100 ml of aqueous solution ?
Answer» 3.0 GM 33.3 gm 29.9 gm 3.33 gm Solution :29.9 gm

Discussion

5.	Gibbs free energy change for the electrolysis process is expressed by ………………… .
Answer» `DELTAG^(@)=-NFE^(@)` `DeltaG^(@)=-NF` `DeltaG^(@)=-nFE^(@)` `DeltaG^(@)=nFE^(@)` ANSWER :A

Discussion

6.	Fructose is not oxidised by bromine water indicates
Answer» the PRESENCE of ALDEHYDIC GROUP presence of ketonic group ABSENCE of aldehydic group absence ofketonic group Solution :absence of aldehydic group

Discussion

7.	Gibbs free energy can be related to cell emf as follows:
Answer» `DELTA G^@ = -nFE_("CELL")` `Delta G^@ = -nFE_("cell")^@` `Delta G = nFE_("cell")` `Delta G^@ = nFE_("cell")^@` ANSWER :B

Discussion

8.	Fructose is a functional isomer of glucose.
Answer» glucose sucrose lactose ribose Answer :A

Discussion

9.	Gibbs energies for the oxidation of Fe and C around 1400""^(@)" are "-341 kJ mol^(-1)" and "-447 kJ mol^(-1). Will C be a suitable reducing agent in the metallurgy of Fe? Give reason.
Answer» Solution :YES. This is because `triangle_(r )G^(0)` for the oxidation of C is more NEGATIVE.

Discussion

10.	Gernera method for the extration of metal from oxide ore is
Answer» CARBON REDUCTION Reduction by alumininum Reduction by hydrogen Electrolytic reduction Solution :Carbon reduction, `Fe_(2)O_(3)+3Cto 2Fe+3CO`.

Discussion

11.	Fructose, fruit sugar, milk sugar, levulose, ketohexose.
Answer» SOLUTION :MILK sugar. It is the NAME of lactose. All OTHERS areindicatingfructose only .

Discussion

12.	Fructose gives the silver mirror test because it
Answer» Contains an aldehyde group Contains a keto group UNDERGOES REARRANGEMENT under the alkaline conditions of the reagent to form a MIXTURE of GLUCOSE and mannose It has pyranose STRUCTURE Answer :C

Discussion

13.	Germinated Barley (an enzyme ) is a source of enzyme :
Answer» ZYMASE Diastase Maltase Invertase Answer :B

Discussion

14.	Fructose contains a keto group but still it reducess Tollens 'reagent. Explain.
Answer» Solution :Under the basic conditions ofTollens' reagent , fructoseundergoes Lobry DE Bruyn van Eikenstein REARRANGEMENT (refer to ' Supplement Your Knowledge for Competitions ').As a result, fructose GIVES a equilibrium mixture of fructose and mannose . Since both GLUCOSE and mannose CONTAIN `-CHO` group , therefore , they reduce Tollen's reagent.

Discussion

15.	Germanium is an example of
Answer» intrinsidc SEMICONDUCTOR n-typesemiconductor p-type semiconductor INSULATOR. ANSWER :A

Discussion

16.	Ge (II) compounds are powerful reducing agents whereas Pb(IV) compound are strong oxidants. It can be due to
Answer» More POWERFUL INERT pair effect in Pb than Ge The ionisation ENERGY `Pb LT IE` of Ge Pb is more electronegative than Ge The ionic radius of `Ge^(2+) and Ge^(4+)` are greter than `Pb^(2+)` and `Pb^(4+)` Answer :A

Discussion

17.	Fructose form hemiketal between gtC=O group and -OH group of
Answer» C-3 C-4 C-5 C-6 Answer :C

Discussion

18.	German silver is an alloy of copper and :
Answer» ZN and Ni Al Zn Sn Answer :A

Discussion

19.	Germanium can be made n-type semi conductor by doping with
Answer» SILICON ARSENIC GALLIUM eitheras or ga Answer :B

Discussion

20.	Frothing agents used to separate ZnS from PbS is……
Answer» NaCN NaCl `NaNO_(3)` `NaNO_(2)` ANSWER :A

Discussion

21.	German silver is an alloy of…
Answer» Copper, Zinc, SILVER Copper, Zinc and Nickel Copper, Zinc and TIN Manganese, CHROMIUM and NI Answer :B

Discussion

22.	Frozen elements of group 18 are called …………………
Answer» SOLUTION :ATOMIC SOLIDS

Discussion

23.	German Silver is an alloy of Copper and:
Answer» Copper, ZINC and NICKEL Copper and silver Copper and tin Copper , zine and silver ANSWER :A

Discussion

24.	Fructose contains
Answer» 5OH groups 3 secondary ALCOHOLIC groups 2 primary alcoholic group and ONE ketonic group All Answer :D

Discussion

25.	German silver is alloys of silver. True / False
Answer» SOLUTION :ALLOY of CU , ZN and NI

Discussion

26.	German silver is an alloy of
Answer» COPPER, zinc and nickel Copper and silver Copper, zinc and tin Copper, zinc and silver Solution :`UNDERSET(60%)(Cu)+underset(205)(Zn)+underset(20%)(NI)`

Discussion

27.	Frothing agent used in froth floatation process is ……………
Answer» PINE OIL olive oil mustard oil neem oil Solution :pine oil

Discussion

28.	Frothers (used in Froth floatation process) are
Answer» MOLECULES with HYDROPHILIC HEAD and HYDROPHOBIC TAIL. molecules with hydrophobic head and hydrophilic tail. both of the above. none of these Solution :molecules with hydrophilic head and hydrophobic tail.

Discussion

29.	German silver is alloys of _____.
Answer» SOLUTION :CU, ZN and NI

Discussion

30.	German silver is a alloy of …… metal.
Answer» ZN, SN, Ni Cu, Sn, Ni Zn, Cu, PB Cu, Zn, Ni ANSWER :D

Discussion

31.	German silver does not contain
Answer» SN Cu ZN NI Solution :German SILVER is an alloy of copper (Cu), zinc (Zn) and nickel (Ni) in the ratio `2 : 1 : 1` . Thus , Sn is not PRESENT in it .

Discussion

32.	German silver contains ____ % of silver.
Answer» 90 10 1 0 Answer :D

Discussion

33.	Froth stabilizers in froth floatation process is...
Answer» CRESOL Pine oil Sodium ethyl XANTHATE Cyanide COMPLEX of sodium Solution :Cresol or aniline are added to stabilize FROTH

Discussion

34.	Gereral formula of primary alcohol is :
Answer» `rarrCOH` `GT CHOH` `-CH_2OH` All Answer :C

Discussion

35.	Froth flotation
Answer» is a physical method of separating MINERAL from the GANGUE is a method to concentrate the ore depending on the difference in wetability of GANGE and there is used for the sulphide ores is a method in which impurities sink to the BOTTOM Solution :This is used to concentrate sulphide ores it is a physical method of separation of mineral from impurity. It is depends on difference in wetability of gangue and ore particles, ore particles wetted by oil and gangue particles wetted by water and settle at bottom.

Discussion

36.	Geometry of XeOF_4 molecule is:
Answer» SQUARE Planar Square PYRAMIDAL Tringular bipyramid Distorted octahedron Answer :B

Discussion

37.	Geometry of the given compound
Answer» CIS TRANS Cis and trans both No GEOMETRICAL isomerism Answer :B

Discussion

38.	Geometry of orbitals around the transition metal ion in hexacyanoferrate
Answer» SQUARE planar ARRANGEMENT tetrahedral arrangement plane trigonal ARRAGEMENT octahedral arrangement ANSWER :D

Discussion

39.	Froth floatation process is used for:
Answer» CUPRITE zincite COPPER PYRITES bauxite Answer :C

Discussion

40.	Geometry of ether is
Answer» linear pyramidal trigonal planar octahedral Answer :B

Discussion

41.	Geometry of orbitals around the transition metal ion in haem of haemoglobin is
Answer» SQUARE PLANAR ARRANGEMENT tetrahedral arrangement PLANE TRIGONAL arragement octahedral arrangement Answer :D

Discussion

42.	Froth floatation process is suitable for concentrating _____ores.
Answer» oxide carbonate sulphide halide Answer :C

Discussion

43.	Geometrical shapes of the complexes (p),(q),(r) formed by the following reactions respectively are : Cu^(2+)(aq)+KCN(aq)("excess")to"complex"(p) Co^(2+)(aq)+KNO_2(s)+H^+ (aq)to"complex"(q) Zm^(2+)(aq)+NaOH(aq)("excess")to"complex"(r)
Answer» Tetrahedral , octahedral and SQUARE PLANAR tetrahedral , octahedral and tetrahedral Square planar , octahedral and tetrahedral Octahedral, octahedral and tetrahedral Solution :(A)`Cu^(2+)(AQ)+4CN^(-)(aq)("excess")to[Cu(CN)_4]^(3-)`(aq)(p) `[Cu(CN)_4]^(3-)-3d^(10)` electron configuration and , therefore , `sp^3` hybridisation and tetrahedral geometry. (B)`Co^(2+)(aq)+3K^(+)(aq)+7NO_2^(-)(s)+2H^(+)(aq)toK_3[Co(NO_2)_6]darr (Q)+NOuarr+H_2O` `[Co(NO_3)_6]^(3-)-3d^(6)` electron configuration and , therefore , `d^2sp^3` hybridisation and octahedral geometry. (C )`Zn^(2+)(aq)+4OH^(-)(aq)("excess")to[Zn(OH)_4]^(2-)(r)` `[Zu(OH)_4]^(2-)3d^10` electron configuration and , therefore , `sp^3` hybridisation and tetrahedral geometry.

Discussion

44.	Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with Cl^(-), CN^(-) and H_(2)O respectively are
Answer» octahedral, tetrahedral and SQUARE planar tetrahedral, square planar and octahedral square planar, tetrahedral and octahedral octahedra, square planar and octahderal. Solution :`Ni^(2+)+Cl^(-)+ Cl^(-)to[NiCl_(4)]^(2-) sp^(3)` hybridisationm, it is tetrahedral. `Ni^(2+)+CN^(-)to[Ni(CN)_(4)]^(2-), dsp^(2)` hybridisation it is square planar. `Ni^(2+)+H_(20Oto[Ni(H_(2)O)_(6)]^(2+), sp^(3)d^(2)` hybridisation, it is octahedral.

Discussion

45.	Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with Cl^(-), CN^(-)and H_2O, respectively, are
Answer» OCTAHEDRAL, TETRAHEDRAL and SQUARE planr Tetrahedral, square PLANAR and octahedral Square planar, tetrahedral and octahedral Octahedral, square planar and octahedral Answer :B

Discussion

46.	Froth floatation process is used for the benefication of :
Answer» OXIDE ore Sulphide ore Carbonate ore Sulphate ore Answer :B

Discussion

47.	Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with Cl^(-), CN^(-) and H_(2)O, respectively, are
Answer» Octahedral, TETRAHEDRAL and square planar Tetrahedral, square planar and octahedral Square planar, tetrahedral and octahedral Octahedral, square planar and octahedral Solution :`NI^(2)+4Cl^(-)rarr[Ni(Cl)_(4)]^(2-)`, tetrahedral, `sp^(3)`, hybridization `Ni^(2+)+4CN^(-)rarr[Ni(CN)_(4)]^(2-)`, square planar, `DSP^(2)` hybridization `Ni^(2)+6H_(2)Orarr[Ni(H_(2)O)_(6)]^(2+)`, octahedral, `sp^(3)d^(2)` hybridization.

Discussion

48.	Froth floatation process is based on
Answer» SPECIFIC gravity of the ore particle magnetic PROPERTIES of the ore PARTICLES. welting properties of the ore particles. ELECTRICAL properties of the ore particles. Answer :C

Discussion

49.	Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with (Cl^(-) CN^(-) and H_(2)0, respectively, are
Answer» octahedral, tetrahedral and SQUARE PLANAR tetrahedral, square planar and octahedral square planar, tetrahedral and octahedral octahedral, square planar and octahedral Solution :`[NiCl_(4)]^(2-) to Tetrahedral` `[Ni(CN)_(4)]^(2-) to Square planar` `[Ni(H_(2)O)_(6)]^(2+) to Octahedral`

Discussion

50.	Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with Cl^-, and CN^-, respectively are
Answer» OCTAHEDRAL, tetrahegral and SQUARE PLANAR Tetrahegral, Octahedral andsquare planar Square planar, tetrahegral and octahedral Octahedral, square planar and tetrahegral Answer :B

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Gibbs free energy G , enthalpy H and entropy S are interrelated as in

Fructose is ketose sugar even then it gives red precipitate with Fehling solution because :

Fructose has a specific rotation -92.4^(@). An aqueous solution of Fructose has an observed rotation of -27.7^(@), when placed in a polarimeter tube of 10 cm long. How much amount of Fructose is dissolved in 100 ml of aqueous solution ?

Gibbs free energy change for the electrolysis process is expressed by ………………… .

Fructose is not oxidised by bromine water indicates

Gibbs free energy can be related to cell emf as follows:

Fructose is a functional isomer of glucose.

Gibbs energies for the oxidation of Fe and C around 1400""^(@)" are "-341 kJ mol^(-1)" and "-447 kJ mol^(-1). Will C be a suitable reducing agent in the metallurgy of Fe? Give reason.

Gernera method for the extration of metal from oxide ore is

Fructose, fruit sugar, milk sugar, levulose, ketohexose.

Fructose gives the silver mirror test because it

Germinated Barley (an enzyme ) is a source of enzyme :

Fructose contains a keto group but still it reducess Tollens 'reagent. Explain.

Germanium is an example of

Ge (II) compounds are powerful reducing agents whereas Pb(IV) compound are strong oxidants. It can be due to

Fructose form hemiketal between gtC=O group and -OH group of

German silver is an alloy of copper and :

Germanium can be made n-type semi conductor by doping with

Frothing agents used to separate ZnS from PbS is……

German silver is an alloy of…

Frozen elements of group 18 are called …………………

German Silver is an alloy of Copper and:

Fructose contains

German silver is alloys of silver. True / False

German silver is an alloy of

Frothing agent used in froth floatation process is ……………

Frothers (used in Froth floatation process) are

German silver is alloys of _____.

German silver is a alloy of …… metal.

German silver does not contain

German silver contains ____ % of silver.

Froth stabilizers in froth floatation process is...

Gereral formula of primary alcohol is :

Froth flotation

Geometry of XeOF_4 molecule is:

Geometry of the given compound

Geometry of orbitals around the transition metal ion in hexacyanoferrate

Froth floatation process is used for:

Geometry of ether is

Geometry of orbitals around the transition metal ion in haem of haemoglobin is

Froth floatation process is suitable for concentrating _____ores.

Geometrical shapes of the complexes (p),(q),(r) formed by the following reactions respectively are : Cu^(2+)(aq)+KCN(aq)("excess")to"complex"(p) Co^(2+)(aq)+KNO_2(s)+H^+ (aq)to"complex"(q) Zm^(2+)(aq)+NaOH(aq)("excess")to"complex"(r)

Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with Cl^(-), CN^(-) and H_(2)O respectively are

Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with Cl^(-), CN^(-)and H_2O, respectively, are

Froth floatation process is used for the benefication of :

Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with Cl^(-), CN^(-) and H_(2)O, respectively, are

Froth floatation process is based on

Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with (Cl^(-) CN^(-) and H_(2)0, respectively, are

Geometrical shapes of the complexes formed by the reaction of Ni^(2+) with Cl^-, and CN^-, respectively are