94420 + Interview Questions in Chemistry in Class 12

1.	Peroxide bond is present in
Answer» MgO CaO `Li_(2)O` `BaO_(2)` ANSWER :D

Discussion

2.	Pernitric acid is
Answer» `HNO_2` `HNO_3` `HNO_4` `HNO` ANSWER :C

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3.	Permutit is:
Answer» HYDRATED SODIUM ALUMINIUM silicate Sodium hexametaphosphate Sodium silicate Sodium META aluminate Answer :A

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4.	Permonosulphuric acid is known as
Answer» Marshall's ACID CARO's acid Sulphuric acid fSulphurous acid Answer :B

Discussion

5.	Permissible noise levels in a residential area at night time is
Answer» 35 db 40 db 50 db 45 db Answer :C

Discussion

6.	Permeanganate ion is not isostructural with
Answer» managanate ion Cromate ion Chlorate ion Perchlorate ion Answer :C

Discussion

7.	Permanganate ion oxidises manganous ion to manganese dioxide in presence of zinc oxide as catatalyst asMnO_(4)^(-) + Mn^(2+) + H_(2)O rarr MnO_(2) + H^(+). The number of H^+ ion added to the product side in the balanced ionic equation is
Answer» SOLUTION :`2MnO_(4)^(-) + 3Mn^(+2) + 2H_2O RARR 2MnO_2+ 3MnO_4 + 4H^(+)`

Discussion

8.	Permanganate ion oxidize S_2O_3^(2-) in fairly alkaline solutions to give
Answer» `SO_(4)^(2-)` `SO_(3)^(2-)` `S^(-2)` S Answer :A

Discussion

9.	Permanganate ion has ……….geometry in which Mn^(7+) is …….. hybridised
Answer» SOLUTION : TETRAHEDRAL, `SP^(3)`

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10.	Permanganate ion is not isostructural with
Answer» MANGANATE ION Cromate ion CHLORATE ion Perchlorate ion ANSWER :C

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11.	Permanganate ion is isostructural with
Answer» Chlorate ion PERCHLORATE ion CHLORITE ion Nitrate ion ANSWER :B

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12.	Permanganate ion changes to……………. in acidic medium.
Answer» `MnO_(4)^(2-)` `Mn^(2+)` `Mn^(3+)` `MnO_(2)` Solution :`MnO_(4)^(-)+ 8H^(+)+ 5e^(-) to Mn^(2+)+ H_(2)O`

Discussion

13.	Permanganateion changes to ________ inacidicmedium
Answer» `MnO_(4)^(2-)` `MN^(2+)` `Mn^(3+)` `MnO_(2)` Solution :`MnO_(4)^(-)+8H^(+)+5e^(-)toMn^(2+)+4H_(2)O`

Discussion

14.	Permanent magnets are generaly made of alloys of :
Answer» Co Zn Sb Pb ANSWER :A

Discussion

15.	Permanent magnets are generally made of alloys of
Answer» Fe Co Ni Any ONE of these Answer :d

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16.	Permanent magnet is made from:
Answer» CAST iron Steel Wrought iron All of these Answer :B

Discussion

17.	Permanent hardness of water cannot be removed by which one of the following methods ?
Answer» Treatment with washing soda CALGON's method Boiling Ion exchange method Solution :Magnesium is a chemical element with symbol Mg. Magnesium is the ninth most abundant element in the universe . Its use as a structural MATERIAL is limited SINCE it burns at relatively low temperatures . Magnesium is frequently alloyed with aluminium , which makes aluminium EASIER to roll , EXTRUDE and weld.

Discussion

18.	Permanent hardness of wateris due to the presence of
Answer» bnicarbonates of sodiumand POTASSIUM CHLORIDES and suphatesof SODIUM andpotassium chlorids and sulphates of calcium and MAGNESIUM BICARBONATES of calcium and magnesium Answer :C

Discussion

19.	Permanenet hardness of water is removed by adding
Answer» SODIUM bicarbonate Washing soda Calcium hydroxide Sodium chloride Answer :B

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20.	Permaganate oxidises aqueous iodide to iodine and itself is reduced to manganese dioxide. How many moles of iodine is liberated with one mole of permanganate ?
Answer» ANSWER :1.5 MOLES

Discussion

21.	Perlong is another name of :
Answer» NYLON - 6 Nylon - 66 Nylon 6,10 Terylene Answer :A

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22.	Perkin's reaction is used for the preparation of which acid?
Answer» BENZOIC acid SALICYLIC acid Cinnamic acid PHTHALIC acid Answer :C

Discussion

23.	Periodic acid splits glucose and fructose into formaldehyde and formic acid. Ratio of moles of formic acid in glucose and fructose is
Answer» `1:2` `5:3` `1:1` `2:3` Solution :`CHO-CHOH - CHOH - underset("Glucose")(CHOH) - CHOH - CH_(2)OH overset(5HIO_(4)) to5HCOOH + HCHO + 5HIO_(3)` `CH_(2)OH - overset(O)overset(\|\|)(C)- underset("FRUCTOSE")(CHOH)- CHOH - CHOH - CH_(2)OH overset(5HIO_(4))to 3HCOOH+ 2HCHO + 5HIO_(3) + CO_(2) + H_(2)O` `therefore ` molar ratio is 5:3

Discussion

24.	Perform the following calculations and calculate the answer to the proper number of significant figures : 144.3 m^2 + (2.54 m x 8.4 m)
Answer» `165.336 m^2` `165m^2` `165.3 m^2` `165.34 m^2` SOLUTION :`2.54 m XX 8.4 m = 21.336m^2 " or" 21m^2` ` 144.3m^2` ` +(21)/(165.3m^2)`

Discussion

25.	Periodic acid is formed by hydrolysis of
Answer» ICl `IP_(3)` `IF_(5)` `IF_(7)` ANSWER :D

Discussion

26.	Perfluorocarbons are remarkable stable, why?
Answer» Solution :The prefix per implies that all the HYDROGEN atoms of a particualr hydrocarbon have been replaced by F atoms. For example. `underset("Perfluorooctane")(CF_(3)(CF_(2))_(6)" or "CF_(3)-CF_(2)-CF_(2)-CF_(2)-CF_(2)-CF_(2)-CF_(2)-CF_(2)`. Since F atom is strongly electronegative and have a very high negative electron gain enthalpy, `C-F` bond is of polar nature. with the increase in the number of F atoms around the CARBON atom, the MAGNITUDE of `+delta` charge on it increases and it acquires more electrostatic force of attraction of `delta`-charge on F atoms. As a result, strenlth of `C-F` bond increases and perfluorocarbons become QUITE stable as well as inert.

Discussion

27.	Perchromic acid (CrO_5) in ether will demposes radily in the presence of H_2SO_4 to form oxygen will produce in thi process
Answer» SOLUTION :`CrO_(5) + H_(2)SO_(4) RARR Cr_2(SO_4)_3 + O_2`

Discussion

28.	Perchloric acid is strongest acid, but weakest oxidising agent. Why?
Answer» Solution :`HClO_(4)` has `pK_(a) lt -10`. Its ability to provide proton is highest. This is due to resonance stabilisation of perchlorate ion. `CIO_(4)^(-)` has four CANNONICAL structures and six delocalised pi ELECTRONS. `CIO_(4)^(-)` is resonance stabilised. It does not furnish OXYGEN and hence a weak oxidant.

Discussion

29.	Perchloric acid is a stronger acid than sulphuric acid.
Answer» Solution :The oxidation state of Cl in perchloric acid is +7 while that of S in sulphur acid is +6 Due to higher oxidation state and higher electronegativity of Cl, `ClO_(3)` part of `HClO_(4)` pulls the electrons of the O-H BOND more strongly and hence can break the O-H bond more easily to liberate a proton than `SO_(2)` partin `H_(2)SO_(4)`. Thus, perchloric acid is a stronger acid than sulphuric acid.

Discussion

30.	Percentages of the free space in cubic close packed structure and is body centered packed structure and is body centered packed structure are respectively.
Answer» 48% and 26% 30% and 26% 26% and 32% 32% and 48% Solution :For FCC or CCP `4r=SQRT(2)arArr P.F.=(nxx(4)/(3)pir^(3))/(a^(3))` `n=4,a=2sqrt(2)r` `P.F.=(4xx(4)/(3)pir^(3))/((2sqrt(2)r)^(3))P.F.=74%` Free space =100-74=26% For BCC `4r=sqrt(3)a` P.F. `=(2xx(4)/(3)pir^(3))/((4)/sqrt(3)r)^(3)`

Discussion

31.	Percentages of free space in cubic close packed structure and in body centered packed structme are respectively
Answer» 30% and 26% 26% and 32% 32% and 48 48% and 26% Solution :Packing fraction is DEFINED as the ratio of the volume of the tmit cell that is occupied by the spheres to the total volume of the UNIT cell. P.F. for ccp and bee are 0.74 and 0.68 respectively. So, the free space in ccp and bee are 26% and 32% respectively

Discussion

32.	Percentages of copper and zinc present in a alloy brass, are respectively
Answer» 60 % and 40% 40% and 60% 0 % and100% 100 % and 0% ANSWER :A

Discussion

33.	Percentage strength of the above H_(2)O_(2) solution is :
Answer» `0.126` `0.272` `0.544` `0.136` Solution :Strength = EQ. MASS `xx` NORMALITY ` = 17 xx 0.16 = 2.72gl^(-1)` ` :. 1000 ` ml SOLN contains ` 2.72` G `:. 100` ml slon contains `0.272` g ` :. ` Percentage of `H_(2)O_(2)` in soln ` = 0.272 %`

Discussion

34.	Percentage strength of 20 volume H_2O_2 solution is
Answer» 0.03 `6%` 0.2 0.15 Answer :B

Discussion

35.	Percentage of silver in the alloy of German silver
Answer» 1.5 2.5 10 zero Answer :D

Discussion

36.	Percentage of H_(2) is maximum in
Answer» `CH_(4)` `C_(6)H_(6)` `C_(2)H_(4)` `C_(2)H_(2)` ANSWER :A

Discussion

37.	Percentage of silver in German silver is :
Answer» `1.5 %` `2.5%` `10%` ZERO PERCENT ANSWER :D

Discussion

38.	Write down the composition of German silver.
Answer» `1.5 %` `2.5%` `10%` ZERO PER CENT ANSWER :D

Discussion

39.	Percentage of silver in german silver…..
Answer» SOLUTION :NA

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40.	Percentage of nickel in nickel steel is :
Answer» `19%` `35%` `39.5%` `8.5%` ANSWER :B

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41.	Percentageofhydrogenismaximum n :
Answer» `C_(2) H_(2)` `C_(2)H_(4)` `C_(2) H_(6)` `CH_(4)` Answer :D

Discussion

42.	Percentage of gold in Fool’s gold is:
Answer» 0 0.08 0.16 0.29 Answer :A

Discussion

43.	Percentage of gold in 20 carat gold is :
Answer» 21.6 90 83.3 70 Answer :B

Discussion

44.	Percentage of gold in 14 carat gold is :
Answer» `58` `80` `40` `14` ANSWER :A

Discussion

45.	Percentage of free space in cubic close packed structure and in body centred packed structure are respectively :
Answer» 32% and 48% 48% and 26% 30% and 26% 26% and 32% Solution :Percentage of FREE space in ccp= 26% and in BCC = 32 %

Discussion

46.	Percentage of free space in a body-centred cubic unit cell is
Answer» 0.32 0.34 0.28 0.3 Answer :A

Discussion

47.	Percentage of empty space in a bcc arrangement is :
Answer» `74%` `68%` `32%` `26%` Answer :C

Discussion

48.	Percentage of carbon in the steels is nearly
Answer» 0.03 0.02 0.002 0.1 Answer :B

Discussion

49.	Percentage of carbon in steel is _____.
Answer» SOLUTION :0.25 to `2.5%`

Discussion

50.	Percentage of a radioactive element decayed after 20 s when half-life is 4 s
Answer» 92.25 96.87 50 75 Solution :`n = (20)/(4) = 5, (N_(t))/(N_(0)) = ((1)/(2))^(5) = (1)/(32), :.` decayed `= (1-(1)/(32)) XX 100 = (31)/(32) xx 100 = 96.87`

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Peroxide bond is present in

Pernitric acid is

Permutit is:

Permonosulphuric acid is known as

Permissible noise levels in a residential area at night time is

Permeanganate ion is not isostructural with

Permanganate ion oxidises manganous ion to manganese dioxide in presence of zinc oxide as catatalyst asMnO_(4)^(-) + Mn^(2+) + H_(2)O rarr MnO_(2) + H^(+). The number of H^+ ion added to the product side in the balanced ionic equation is

Permanganate ion oxidize S_2O_3^(2-) in fairly alkaline solutions to give

Permanganate ion has ……….geometry in which Mn^(7+) is …….. hybridised

Permanganate ion is not isostructural with

Permanganate ion is isostructural with

Permanganate ion changes to……………. in acidic medium.

Permanganateion changes to ________ inacidicmedium

Permanent magnets are generaly made of alloys of :

Permanent magnets are generally made of alloys of

Permanent magnet is made from:

Permanent hardness of water cannot be removed by which one of the following methods ?

Permanent hardness of wateris due to the presence of

Permanenet hardness of water is removed by adding

Permaganate oxidises aqueous iodide to iodine and itself is reduced to manganese dioxide. How many moles of iodine is liberated with one mole of permanganate ?

Perlong is another name of :

Perkin's reaction is used for the preparation of which acid?

Periodic acid splits glucose and fructose into formaldehyde and formic acid. Ratio of moles of formic acid in glucose and fructose is

Perform the following calculations and calculate the answer to the proper number of significant figures : 144.3 m^2 + (2.54 m x 8.4 m)

Periodic acid is formed by hydrolysis of

Perfluorocarbons are remarkable stable, why?

Perchromic acid (CrO_5) in ether will demposes radily in the presence of H_2SO_4 to form oxygen will produce in thi process

Perchloric acid is strongest acid, but weakest oxidising agent. Why?

Perchloric acid is a stronger acid than sulphuric acid.

Percentages of the free space in cubic close packed structure and is body centered packed structure and is body centered packed structure are respectively.

Percentages of free space in cubic close packed structure and in body centered packed structme are respectively

Percentages of copper and zinc present in a alloy brass, are respectively

Percentage strength of the above H_(2)O_(2) solution is :

Percentage strength of 20 volume H_2O_2 solution is

Percentage of silver in the alloy of German silver

Percentage of H_(2) is maximum in

Percentage of silver in German silver is :

Write down the composition of German silver.

Percentage of silver in german silver…..

Percentage of nickel in nickel steel is :

Percentageofhydrogenismaximum n :

Percentage of gold in Fool’s gold is:

Percentage of gold in 20 carat gold is :

Percentage of gold in 14 carat gold is :

Percentage of free space in cubic close packed structure and in body centred packed structure are respectively :

Percentage of free space in a body-centred cubic unit cell is

Percentage of empty space in a bcc arrangement is :

Percentage of carbon in the steels is nearly

Percentage of carbon in steel is _____.

Percentage of a radioactive element decayed after 20 s when half-life is 4 s