94420 + Interview Questions in Chemistry in Class 12

1.	Distinguish between absorption and adsorption.
Answer» SOLUTION :

Discussion

2.	Distinguish between (a) Ethanol and phenol (b) Phenol and acetic acid ( c) Phenol and ( d) Phenol and anisole.
Answer» SOLUTION :

Discussion

3.	Distinguish between A and B?c) Give two examples of crystals showing this defect.
Answer» SOLUTION :fig.A-Ideal crystal. Fig.B.-Frenkel DEFECT

Discussion

4.	Distinguish betwee: (i) ethyl alcohol and acetaldehyde (ii) C_(6)H_(6)COCH_(3) and C_(6)H_(5)CH_(2)CHO
Answer» Solution :(i) ADD Na metal, Ethyl alcohol gives `H_(2)` gas whereas ACETALDEHYDE does not react. (ii) Add `I_(2)` and NaOH, acetophenone `(C_(6)H_(5)COCH_(3))` will give YELLOW PPT. of iodoform whereas `C_(6)H_(5)CH_(2)CHO` will not react.

Discussion

5.	Distinction in 1-pentene and 1-pentyne is done by
Answer» `[AG(NH_3)_2]^+` CONC. `H_2SO_4` HCL `Br_2` ANSWER :A

Discussion

6.	Distinction of 1^(@), 2^(@) and 3^(@) alcohols is done by ______ test.
Answer» LUCAS VICTOR MEYER Hoffmann both (a) and ( C) ANSWER :D

Discussion

7.	Distinction between primary, secondary and tertiary alcohol is done by
Answer» OXIDATION method Lucas test silver MIRROR test both 'a' and 'b' Answer :D

Discussion

8.	Distillation under reduced pressure is used to purify liquids which :
Answer» are HIGHLY volatile have HIGH BOILING points decompose below their boiling points are explosives Answer :C

Discussion

9.	Distillation of sodium salt of benzoic acid with soda lime gives:
Answer» Benzene Toluene Benzaldehyde Xylene. Answer :A

Discussion

10.	Distillation of bleaching powder and acetone gives
Answer» `CHCl_(3)` CHLORAL `CH_(3)Cl` `C Cl_(4)` SOLUTION :`CHCl_(3)`

Discussion

11.	Distillation is used for the refining of:
Answer» `FE` `ZN` `Zn` `CU` ANSWER :B

Discussion

12.	Distillation of acetone with conc. sulphuric acid gives
Answer» diacetone alcohol mesityl oxide mesitylene propene-2-ol. Solution :Distillation of ACETONE with CONC. `H_(2)SO_(4)` gives mesitylene. `CH_(3)COCH_(3) UNDERSET("HEAT")overset(Conc. H_(2)SO_(4))to "Mesitylene"`

Discussion

13.	Distillation involves all the following processes except :
Answer» CHANGE of STATE BOILING CONDENSATION evaporation Solution :N//A

Discussion

14.	Dissymmetric molecule are those which, are
Answer» NON SUPER IMPOSABLE MIRROR IMAGE super imposable mirror image plane of symmetry plane of symmetry Answer :A

Discussion

15.	Dissoution of iodine crystals in carbon tetrachlorides solvent can be attributed to
Answer» Hydeogen bonding between them dipole-induced dipole interactin between them London dispersion FORCE between them Large molecular MASS of iodine and HENCE large van-der waals forces Answer :C

Discussion

16.	Dissolving metallic Zn in excess of NaOH produces :-
Answer» NA2ZNO2 Zn(OH)2 ZNO Zn(OH)2 & Na2ZnO2 SOLUTION :NAOH + Zn —` to` Na2ZnO2 + H2

Discussion

17.	Dissolving NaCN in de-ionized water will result in a solution having
Answer» `PHlt7` `pH =7` `POH =7` `pH gt 7` SOLUTION :Hydrolysisof NaOH ` NaCH +H_2 O hArrunderset("strong BASE ")(NaOH)+ underset("weak acid")(HCN)` hencethe resulting solution will be BASIC:` pHgt 7`

Discussion

18.	Dissolving NaCN in demonized water will result in a solution having
Answer» pH>7 pH=7 pOH=7 pH<7 Solution :`CN^-+H_2O Such anionic hydrolysis MAKES the solution alkaline.

Discussion

19.	Dissolving 120g of urea (mol.wt.60) in 1000g of water gave a solution of density 1.15 g/mL. The molarity of the solution is
Answer» 1.78 M 2.00 M 2.05 M 2.22 M SOLUTION :Mole `=(120)/(60)=2` mass of solution = 1120 g `V=(1120)/(1.15xx100)=(112)/(115)L` `M=(2xx115)/(112)=2.05` mol/litre

Discussion

20.	Dissolving metallic zinc in access of NaOH produces:
Answer» `Zn(OH)_2` `Na_2ZnO_2` ZnO `Zn(OH)_2 and Na_2ZnO_2` ANSWER :B

Discussion

21.	Dissolving 120g of urea (mol wt = 60) in 1000g of water gave a solution of density 1.15 g/mL. The molarity of the solution is
Answer» `1.78` M `2.00` M `2.05` M `2.22` M SOLUTION :VOLUME of solution=mass of solution `XX` DENSITY

Discussion

22.	Dissolving 120 g of urca (mol . Wi 60) in 1000 gof water gave a solution of density 1.15 g/mL the molarity of the solution is
Answer» `1.78` M `2.00`M `2.05` M `2.22` M SOLUTION :NUBER of MOLES of urea `= (120)/(60)=2` Total mass of solution `=1000+120=1120g ` Total VOLUME of solution (in L) `= ("Mass)/("Density") =(1120)/(1.15xx10^(3))=(112)/(115)l.` MOLARITY of the solution `= ("Number of moles")/("Volume of solution litre")=(2xx115)/(112) =2.05 mol L ^(-1)`

Discussion

23.	Dissolved oxygen values of four water samples A,B,C and D are respectively 6 ppm, 5 ppm, 1 ppm and 3 ppm. Which is polluted?
Answer» Solution :LESSER the DO VALUE GREATER the extent of pollution of water. THUS, C is the most polluted water sample.

Discussion

24.	Dissolving 120 g of urea (molecular mass = 60) in 1000 g of water gave a solution of density 1.15 g/mL. The molarity of the solution is :
Answer» `1.78 M` `2.00 M` `2.05 M` `2.22 M` Solution :Total MASS of solution =1000+120=120=1120 g Total VOLUME of solution `="Mass"/"Density"=((1120g))/((1.15"g mL"^(-1)))` =973.91.= mL `"Molarity(M)"=("GRAM moles of solute")/("Volume of solution in liters")` `=((120g//60"g MOL"^(-1)))/((973.91//1000L))=2.05 "mol L"^(-1)` =2.05 M.

Discussion

25.	Dissolved oxygen in water is needed only by aquatic animals and plants . Comments.
Answer» Solution :DISSOLVED oxygen is not only NEEDED by aquatic flora and fauna but also makes fit for drinking.

Discussion

26.	Dissolution of sugar being an endothermic reaction is favoured by :
Answer» LOW T High T High P Low P Answer :B

Discussion

27.	Dissolution of calcium chloride in water is exothermicprocess while that of ammonium nitrate is endothermic process, the observation is
Answer» Solubility of CALCIUM chloridedecreases with increase in temperature and that of AMMONIUM nitrate increases with increase in temperature Solubilities of both decreases with increase in temperature Solubilities of both increases with increase in temperature Solubilities of calcium CHLORIDE increases with increase in temperature and that of ammonium nitrate decrease with increase in temperature Solution :For exothermic process increasing temperature , solubility decreases. For ENDOTHERMIC process increasing temperature, solubility increases.

Discussion

28.	Dissolution of 1.28 g of sulphur in 50g of CS_(2) causes the freezingpoint of solvent to be lowered by 0.010^(@). If the sulphur molecule could be represented by S_(x) then x=_________(K_(f)=0.1 KKg "mol"^(-1))
Answer»

Discussion

29.	Dissolution of a solute is an exothermic process if:
Answer» HYDRATION ENERGY > Lattic energy Hydration energy < Lattic energy Hydration energy=Lattic energy None Answer :A

Discussion

30.	Dissolution of a solute is an exothermic process if
Answer» HYDRATION energy gt LATTICE energy Hydrationenergy lt Lattice energy Hydration energy = Lattice energy None Solution :`Delta H_("solution")= Delta H_("hydration") + Delta H_("latticeenergy")` `Delta H_(H) = -ve``Delta H_(1) = + ve `

Discussion

31.	Dissolution of 1.5g of a non-volatile solute (mol., wt. = 60) in 250 g of a solvent reduces its frezzing point by 0.01^(@)C . Find the molal depression constant of the solvent.
Answer» `0.01` `0.001` `0.0001` `0.1` Solution :DEPRESSION in frezzing point , `Delta T_(f) = k_(f) xx m` where , m= molality = `("WT. of solute" xx 1000)/("MOL. Wt. of solute") xx "wt. of solvent" ` `= (1.5 xx 1000)/(60 xx 250)` `=0.1` `IMPLIES Delta T_(f) = k_(f) xx 0.1` `0.01 = k_(f) xx 0.1` `therefore k_(f) = (0.01)/(0.1)` `= 0.1 ^(@)C "molal"^(-1)`

Discussion

32.	Dissociation of NH_(4)OH is decreased in presence of :-
Answer» `CH_(3)COOH` KOH `HNO_(3)` NONE of these Answer :2

Discussion

33.	Dissociation of H_(3)PO_(4) takes place in following steps
Answer» 1 2 3 4 Solution : `H_(3)PO_(4) OVERSET("I step")hArr H^(+) + H_(2)PO_(4)^(-)` `H_(2)PO_(4)^(-) overset("II step")hArr + HPO_(4)^(--)` `HPO_(4)^(--) overset("III step")hArr H^(+) + PO_(4)^(---)`

Discussion

34.	Dissociation of H_(2)SO_(4) takes place during
Answer» CHARGING of cell discharging of cell decomposition of cell maintainance of the lead ACCUMULATOR Solution :38% `H_(2)SO_(4)` with 1.2 g/ML density is used in lead accumulator. `M=(W)/(m)xx(1000)/(100xxd)=(38)/(98)xx(1000)/(100xx1.2)=3.2 M`

Discussion

35.	Dissociation of an indicator can be considered as Hln hArr H^(+)+ln^(-). Colour of Hln is P and ln^(-) is Q. Given the ratio of concentration of Hln to ln^(-) ranges from 10 to 1//10 then which of the following statements are correct.
Answer» SOLUTION assumes P COLOUR, when `PH lepK_(ln-1)` Solution assumes P colour, when `pH GE pH _(ln-1)` Solution assumes Q colour , when `pH gepK_(ln-1)` Solution assumes Q colour , when `pH lepK_(ln-1)` Solution :MAXIMUM pH to see distinct colour is `pK_(ln-1)` and minimum pH to see a colour is `pK_(ln+1)`

Discussion

36.	Dissociation of a salt A_(2)B_(3)(aq) in water follows first order kinetics in terms of concentration of [A_(2)B_(3)] as A_(2)B_(3)(aq)to2A^(+3)(aq)+3B^(2-)(aq). Starting from t=0, solution is taken out at different instant and its osmotic rise is measured. From the given data calculate abcd. ab=t_(3//4) of the dissociation of A_(2)B_(3) in water in minutes. cd= Osmotic pressure in Pascal after 20 min.density of solution is 1 g//mL. {:(,"Given data :",t=0,t=10 min,),(,"osmotic rise",2 mm,6 mm,):}
Answer» ANSWER :2080

Discussion

37.	Dissociation equilibrium constant of HI is 2.06xx10^(-2) at 458^(@)C. At equilibrium, concentrations of HI and I_(2) are 0.36M and 0.15M respectively. What is the equilibrium concentration of H_(2) at 458^(@)C.
Answer» ANSWER :`[H_(2)]=1.78xx10^(-2)M`

Discussion

38.	Dissociation constant of NH_4OH is 1.8xx10^-5 the hydrolysis constant of NH_4 CI would be
Answer» `1.8xx10^(-19)` `5.55xx10^(-10)` `5.55xx10^(-5)` `1.80xx10^(-5)` ANSWER :B

Discussion

39.	Dissociation constant of NH_4OH is 1.8 times 10^-5 the hydrolysis constant of NH_4Cl would be …….
Answer» `1.8 TIMES 10^-19` `5.55 times 10^-10` `5.55 times 10^-5` `1.80 times 10^-5` SOLUTION :`K_h=K_w/K_b=(1.8 times10^-14)/(1.8 times10^-5)=0.55 times10^-9=5.5 times10^-10`

Discussion

40.	Dissociation constant of a weak acid is decreased by
Answer» Addition of a strong acid Addition of a SALT of the above weak acid Decreasing temperature DILUTION of the solution Solution :VALUE of dissociation constant 'K' of weak acid is constant at particular temperature. Hence, it DECREASES on decreasing the temperature and increases on INCREASING temperature.

Discussion

41.	Displacementof the hydroxy1 group of alcohol can take place with variety of reagents. One such reaction is HBr+CH_(3) CH_(2)OH to CH_(3)CH_(2)Br+H_(2)O The above reaction has a two-step mechanism. (a) CH_(3)CH_(2)OH+H^(+)overset(k_(eq))(hArr) CH_(3)CH_(2)OH_(2)^(+) (b) CH_(3)CH_(2)OH_(2)^(+)+Br^(-) overset(k_(2))(to)CH_(3)CH_(2)Br+H_(2)O The slow and fast can be identified by the fact that rate of displacement of hydroxyl by halide ions depends on the type of halide ion . Calculate the rate of the formation of Ethyl Bromide when concentration of alcohol is 0.5 M and HBr is 10^(-1) M. Assume complete dissociation of HBr. Express your answer in terms of 10^(-6) M//sec. ["Given" : K_(eq) = 4M ^(-1)"and" K_(2) = 5xx10^(-2) M^(-1) sec^(-1)]
Answer» ANSWER :1000

Discussion

42.	Disproportionation raects w.r.t. Cl_(2) is
Answer» `Cl_(2) + UNDERSET("(excess)")(NH_(3)) RARR` ` underset("(excess)")(Cl_(2)) + NH_(3) rarr` `Cl_(2)+ H_(2) O rarr ` `Cl_(2) + O_(2) rarr` SOLUTION :`3Cl_(2) + underset("(Excess)")(8NH_(3)) rarr N_(2) + 6 NH_(4) Cl , 3Cl_(2) + 4NH_(3) rarr NCl_(3) + 3NH_(4) Cl`

Discussion

43.	Dispersion of tear gas happens during riots, the formula of tear gas is
Answer» `COCl_2` `C Cl_3NO_2` `CHCl_2NO_2` `CHCl_3` ANSWER :B

Discussion

44.	Dispersion force is present between :-
Answer» POLAR + Polar molecules NONPOLAR + Non-polar molecules Polar + Nonpolar molecules All of these Answer :D

Discussion

45.	Dispersed phase and dispersion medium are two phases of colloidal system. Name the colloid in which dispersed phase is liquid and dispersion medium is solid.
Answer» Sol Foam Emulsion Gel Answer :A

Discussion

46.	Disperse phase and the dispersion media in blood respectively are (M-2007)
Answer» LIQUID, solid Liquid, liquid Solid, liquid Solid, solid Answer :C

Discussion

47.	Disperse phase and dispersion medium in butter are respectively
Answer» SOLID and liquid liquid and solid liquid and liquid solid and solid Solution :Disperse phase and DISPERSION MEDIUM in BUTTER are liquid and solid respectively.

Discussion

48.	Disodium pentacyanonitrosyl ferratereagent gives purple colour when which of thefollowing element is present.
Answer» `N` `CL` `F` `S` ANSWER :D

Discussion

49.	Disodium hydrogen phosphate is used to test
Answer» `Mg^(+2)` `NA^(+)` `CA^(+2)` `Zn^(2+)` ANSWER :A

Discussion

50.	Disodiumhydrogen phosphate is used to test :
Answer» `Na^(+)` `CA^(2+)` `MG^(2+)` `CU^(2+) ` ANSWER :C

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Distinguish between absorption and adsorption.

Distinguish between (a) Ethanol and phenol (b) Phenol and acetic acid ( c) Phenol and ( d) Phenol and anisole.

Distinguish between A and B?c) Give two examples of crystals showing this defect.

Distinguish betwee: (i) ethyl alcohol and acetaldehyde (ii) C_(6)H_(6)COCH_(3) and C_(6)H_(5)CH_(2)CHO

Distinction in 1-pentene and 1-pentyne is done by

Distinction of 1^(@), 2^(@) and 3^(@) alcohols is done by ______ test.

Distinction between primary, secondary and tertiary alcohol is done by

Distillation under reduced pressure is used to purify liquids which :

Distillation of sodium salt of benzoic acid with soda lime gives:

Distillation of bleaching powder and acetone gives

Distillation is used for the refining of:

Distillation of acetone with conc. sulphuric acid gives

Distillation involves all the following processes except :

Dissymmetric molecule are those which, are

Dissoution of iodine crystals in carbon tetrachlorides solvent can be attributed to

Dissolving metallic Zn in excess of NaOH produces :-

Dissolving NaCN in de-ionized water will result in a solution having

Dissolving NaCN in demonized water will result in a solution having

Dissolving 120g of urea (mol.wt.60) in 1000g of water gave a solution of density 1.15 g/mL. The molarity of the solution is

Dissolving metallic zinc in access of NaOH produces:

Dissolving 120g of urea (mol wt = 60) in 1000g of water gave a solution of density 1.15 g/mL. The molarity of the solution is

Dissolving 120 g of urca (mol . Wi 60) in 1000 gof water gave a solution of density 1.15 g/mL the molarity of the solution is

Dissolved oxygen values of four water samples A,B,C and D are respectively 6 ppm, 5 ppm, 1 ppm and 3 ppm. Which is polluted?

Dissolving 120 g of urea (molecular mass = 60) in 1000 g of water gave a solution of density 1.15 g/mL. The molarity of the solution is :

Dissolved oxygen in water is needed only by aquatic animals and plants . Comments.

Dissolution of sugar being an endothermic reaction is favoured by :

Dissolution of calcium chloride in water is exothermicprocess while that of ammonium nitrate is endothermic process, the observation is

Dissolution of 1.28 g of sulphur in 50g of CS_(2) causes the freezingpoint of solvent to be lowered by 0.010^(@). If the sulphur molecule could be represented by S_(x) then x=_________(K_(f)=0.1 KKg "mol"^(-1))

Dissolution of a solute is an exothermic process if:

Dissolution of a solute is an exothermic process if

Dissolution of 1.5g of a non-volatile solute (mol., wt. = 60) in 250 g of a solvent reduces its frezzing point by 0.01^(@)C . Find the molal depression constant of the solvent.

Dissociation of NH_(4)OH is decreased in presence of :-

Dissociation of H_(3)PO_(4) takes place in following steps

Dissociation of H_(2)SO_(4) takes place during

Dissociation of an indicator can be considered as Hln hArr H^(+)+ln^(-). Colour of Hln is P and ln^(-) is Q. Given the ratio of concentration of Hln to ln^(-) ranges from 10 to 1//10 then which of the following statements are correct.

Dissociation equilibrium constant of HI is 2.06xx10^(-2) at 458^(@)C. At equilibrium, concentrations of HI and I_(2) are 0.36M and 0.15M respectively. What is the equilibrium concentration of H_(2) at 458^(@)C.

Dissociation constant of NH_4OH is 1.8xx10^-5 the hydrolysis constant of NH_4 CI would be

Dissociation constant of NH_4OH is 1.8 times 10^-5 the hydrolysis constant of NH_4Cl would be …….

Dissociation constant of a weak acid is decreased by

Disproportionation raects w.r.t. Cl_(2) is

Dispersion of tear gas happens during riots, the formula of tear gas is

Dispersion force is present between :-

Dispersed phase and dispersion medium are two phases of colloidal system. Name the colloid in which dispersed phase is liquid and dispersion medium is solid.

Disperse phase and the dispersion media in blood respectively are (M-2007)

Disperse phase and dispersion medium in butter are respectively

Disodium pentacyanonitrosyl ferratereagent gives purple colour when which of thefollowing element is present.

Disodium hydrogen phosphate is used to test

Disodiumhydrogen phosphate is used to test :