94420 + Interview Questions in Chemistry in Class 12

1.	KMnO_(4)gets reduced to
Answer» `K_(2)MnO_(4)` in neutral medium `MnO_(2)` in acidicmedium `MN^(2+)` in ALKALINE medium `MnO_(2)` in neutralmedium SOLUTION :`KMnO_(4)` is reduced to `MnO_(2)` in neutral medium `2KMnO_(4) + H_(2)O rarr 2MnO_(2)+ 2KOH+3(O)` or `MnO_(4)^(-) + 2H_(2)O+ 3E^(-) rarr MnO_(2) + 4OH^(-)` In alkaline medium, it is reduced to `K_(2)MnO_(4)` or `MnO_(2)` . In acidic medium, it is reduced to `Mn^(2+)`

Discussion

2.	KMnO_(4),and K_(2)Cr_(2)O_(7) are replaced in volumetric analysis by
Answer» LA(III) salts Ce (III) salts Ce (IV) salts Gd (III) salts Answer :C

Discussion

3.	KMnO_(4)acts as an oxidising agent in acidic medium. The number of moles of KMnO_(4) that will be needed to react with one mole of sulphide ions in acidic solution is:
Answer» `(2)/(5)` `(3)/(5)` `(4)/(5)` `(1)/(5)` ANSWER :a

Discussion

4.	KMnO_4 will oxidised acetylene to
Answer» ETHYLENE glycol Ethyl alcohol Oxalic ACID Acetic acid Solution :`{:(CHoverset(KMnO_4)to,COOH),("\|\|\|","\|"),("Acetylene","Oxalic acid"):}`

Discussion

5.	KMnO_(4) reacts with oxalic acid according to the equation 2MnO_(4)^(-)+5C_(2)O_(4)^(2-)+16H^(+) to 2Mn^(2+)+10CO_(2)+8H_(2)O Here, 20 mL of 0.1 M KMnO_(4) is equivalent to:
Answer» 120 ML of 0.25 M `H_(2)C_(2)O_(4)` 150 mL of 0.10M `H_(2)C_(2)O_(4)` 25 mL of 0.20 M `H_(2)C_(2)O_(4)` 50 mL of 0.20 M `H_(2)C_(2)O_(4)` Answer :C

Discussion

6.	KMnO_(4) reacts with KI in basic medium to from I_(2) and MnO_(2). When 250 mL of 0.1 M KI solution is mixed with 250 mL of 0.02 M KMnO_(4) in basic medium, what is the number of moles I_(2)formed ?
Answer» 0.015 0.0075 0.005 0.01 Answer :B

Discussion

7.	KMnO_4 oxidises oxalic acid in acidic medium. The number of CO_2 molecules produced as per the balanced equation is
Answer» 10 8 6 3 Solution :(a) 10 MOLES of CO, are PRODUCED.

Discussion

8.	KMnO_(4) on heating to red hot gives
Answer» `K_(2)MnO_(4)+ MnO_(2)+O_(2)` `K_(2)MnO_(3) + MnO_(2)+ O_(2)` `K_(2)O+ MnO_(2)+ O_(2)` None of these Answer :B

Discussion

9.	KMnO_4 oxidises oxalates to ____
Answer» CO `CO_3^(2-)` `CO_2` `HCO_3^-` ANSWER :C

Discussion

10.	KMnO_4 oxidation of which of the following will produce terephthalic acid?
Answer» o-xylene m-Diemethyl BENZENE p-Diethyl benzene m-xylene Solution : In this (A) gives phthalic ACID while (B) and (D) GIVE isophthalic acid.

Discussion

11.	KMnO_(4) on reaction with KOH does not give…
Answer» `H_(2)O` `MnO_(2)` `K_(2)MnO_(4)` `[O]` Solution :`K_(2)MnO_(4), H_(2)O and [O]` are OBTAINED as products

Discussion

12.	KMnO_4 on heating above 200@C gives:
Answer» `K_2MnO_3 + O_2 + MnO_2` `K_2MnO_4 + MnO_2 + O_2` `MnO_2 + O_2` None Answer :A

Discussion

13.	KMnO_(4) is prepared by
Answer» passing `Cl_(2)` through `K_(2)MnO_(4)` SOLUTION passing `O_(2)` through `K_(2) MnO_(4)` solution reaction of KOH with `KMnO_(4)` Fusion of KOH with `MnO_(2)` Solution :Passing `Cl_(2) ` through `K_(2) MnO_(4)` solution.

Discussion

14.	KMnO_4 is prepared by:
Answer» PASSING `Cl_2` through `K_2MnO_4` solution Passing `O_2` through `K_2MnO_4` solution Reaction of KOH with `KMnO_4` FUSING KOH with `MnO_2` ANSWER :A

Discussion

15.	KMnO_(4) is iso stuctural with
Answer» `KClO_(4)` `HClO_(4)` `K_(3)BO_(3)` None Solution :`KMnO_4` has tetrahedral structure, Same for `KClO_4, HClO_4`

Discussion

16.	KMnO_(4) is oxo salt of….
Answer» `MnO_(2)` `MnO_(3)` `Mn_(2)O_(7)` `Mn_(2)O_(3)` Solution :`Mn_(2)O_(7) + 2KOH rarr 2KMnO_(4) + H_(2)O`

Discussion

17.	KMnO_(4) in alkaline medium changes to ….
Answer» `MN^(3+)` `MnO_(2)` `MnO_(4)^(2-)` `Mn(OH)_(4)^(-)` Solution :`2KMnO_(4) + H_(2)O overset(-OH)rarr 2MnO_(2) + 2KOH + 3[O]`

Discussion

18.	KMnO_(4) is powerful oxidant where it converts into
Answer» `MnO_(4)^(2-)` `MnO_(2)` `MN^(2+)` `Mn^(3+)` Answer :B

Discussion

19.	KMnO_(4) does not act as oxidising agent in the presence of HCI. Why?
Answer» SOLUTION :HCl cannot be used for making ACIDIFIED `KMnO_(4)` as OXIDISING agent, since it reacts with `KMnO_(4)` as FOLLOWS `2MnO_(4)^(-)+10CI^(-) + 16H^(+) to2Mn^(2+) + 5Cl_(2) +8H_(2)O`

Discussion

20.	KMnO_(4) can be prepared from K_(2)MnO_(4) as per the reaction 3MnO_(4)^(2-) + 2H_(2)O hArr 2MnO_(4)^(2-) + MnO_2 + 4OH^- The reaction can go to completion by removing OH^(-) ions by adding.
Answer» KOH `CO_2` `SO_2` HCl Answer :B

Discussion

21.	KMnO_(4) does not act as oxidising agent in the presence of HCl. Why ?
Answer» Solution :HCL cannot be used for making acidified `KMnO_(4)` as oxidising AGENT, SINCE it reacts with `KMnO_(4)` as FOLLOWS. `2MnO_(4)^(-) + 10 Cl^(-) + 16H^(+) rarr 2Mn^(2+) + 5Cl_(2) + 8H_(2)O`

Discussion

22.	KMnO_4 can not oxidize
Answer» `NO_(2)^(-)` `FE^(2+)` `CL^(-)` `F^(-)` ANSWER :D

Discussion

23.	KMnO_(4) can be prepared from K_(2)MnO_(4)as per the reaction : 3MnO_(4)^(2-) + 2H_(2)O hArr2MnO_(4)^(-) + 4OH^(-) Thereaction can go to completion by removing OH^(-) ions by adding
Answer» HCl KOH `CO_(2)` `SO_(2)` Solution :`3MnO_(4)^(2-) + 2H_(2)O hArr 2MnO_(4)^(-) + MnO_(2) + 4OH^(-)` The reactioncan GOTO completion by removing `OH^(-)` ions by adding `CO_(2)` as it reacts with `OH^(-)` ion to form `CO_(3)^(2-)` ions `4OH^(-) + 2CO_(2) rarr2CO_(3)^(2-) + 2H_(2)O`

Discussion

24.	KMnO_(4) can be prepared from K_(2)MnO_(4) as per the reaction, 3MnO_(4)^(2-)+2H_(2)O hArr 2MnO_(4)^(2-)+MnO_(2)+4OH^(-) The reaction can go to completion by removing OH^(-) ions by adding.
Answer» KOH `CO_(2)` `SO_(2)` `KCl` Solution :HCl and `SO_(2)` are reducing AGENTS and can REDUCE `MnO_(4)^(-).CO_(2)` which is neither oxidising and nor reducing will provide only acidic medium. It can shift reaction in forward direction and reaction can go to COMPLETION.

Discussion

25.	KMnO_(4) can be prepared from K_(2)MnO_(4) as per reaction 3MnO_(4)^(2-)+2H_(2)OhArr2MnO_(4)^(-)+MnO_(2)+4OH^(-)
Answer» HCl KOH `CO_(2)` is formed as the product `sO_(2)` Solution :Since,`OH^(-)` are generated from weak acid`(H_(2)O)`. A weak acid (like `CO_(2)`) should be used to remove it because strong acid (HCl) reverse the reaction . KOH INCREASES the concentration of `OH^(-)`,thus again sgifts the reaction in backward side . `Co_(2)` COMBINES with `OH^(-)` to give carbonate which is easily removed. `SO_(2)`react with water to give strong acid , so it cannot be used.

Discussion

26.	KMnO_(4) can be prepared from K_(2)MnO_(4) as per the reaction 3MnO_(4)^(2-)+2H_(2)O hArr 2MnO_(4)^(-)+MnO_(2)+4OH^(-) The reaction can go to completion by removing OH^(-) ions by adding
Answer» `SO_(2)` `HCL` `KOH` `CO_(2)` ANSWER :D

Discussion

27.	KMnO_4 acts as oxidising agent in
Answer» ACIDIC medium neutral medium alkaline medium all of the above Answer :D

Discussion

28.	KMnO_(4) acts as an oxidizing agent in acidic medium. The number of moles of KMnO_(4) that will be needed to react with one moleof sulphide ions in acidic solution is
Answer» `(2)/(5)` `(3)/(5)` `(4)/(5)` `(1)/(5)` Solution :`2KMnO_(4)+ 3H_(2)SO_(4) rarr K_(2)SO_(4) + 2MnSO_(4) + 3H_(2)O + 5(O)` `H_(2)S+ (O) rarrH_(2)OI +S ] xx 5` `bar ( 2KMnO_(4) + 3H_(2)SO_(4) + 5H_(2)Srarr K_(2)SO_(4) + 8 H_(2)O5S)` 1 mole of `S^(2-)` ions will required`KMnO_(4) = ( 2)/( 5) `moles

Discussion

29.	KMnO_(4) acts as an oxidising agent in the presence of dil H_2 SO_4. Its equivalent weight is (M is molecular weight)
Answer» `M/(2)` `M` `M/5` `M/3` ANSWER :C

Discussion

30.	KMnO_(4) acts as an oxidising agent in alkaline medium. When alkaline KMnO_(4) is treated with KI, iodide ion is oxidised to "…........."
Answer» SOLUTION :`2KMnO_(4) + H_(2)O + KIrarr 2MnO_(2) + 2KOH + KIO_(3)` or `I^(-)+ 6OH^(-) RARR IO_(3)^(-) + 3H_(2)O + 6E^(-)`

Discussion

31.	KMnO_(4) acts as an oxidising agent in alkaline medium. When alkaline KMnO_(4) is treated with KI, iodide ion is oxidised to …..
Answer» `I_(2)` `IO^(-)` `IO_(3)^(-)` `IO_(4)^(-)` SOLUTION :`I^(-) + 2MnO_(4)^(-) + H_(2)O rarr 2OH^(-) + 2MnO_(2) + IO_(3)^(-)`

Discussion

32.	KMnO_(4) acts as an oxidising agent in acidic medium. When alkaline KMnO_4 is treated with KI, iodide ion is oxidised to
Answer» `I_2` `IO^(-)` `IO_(3)^(-)` `IO_(4)^(-)` SOLUTION :`2KMnO_4 + KL + H_2O RARR 2MnO_2 + 2KOH + KIO_3`

Discussion

33.	KMnO_(4) acts as an oxidising agent in alkaline medium. When alkaline KMnO_(4) is treated with KI, iodide ion is oxidised to……… .
Answer» `I_2` `IO^(-)` `IO_(3)^(-)` `IO_(4)^(-)` SOLUTION :`2KMnO_4 + Kl + H_2O rarr 2MnO_2 + 2KOH + KIO_3`

Discussion

34.	It is found that 16.5 g of metal combine with oxygen to form 35.60 g of metal oxide. Calculate the percentage of metal and oxygen in the compound.
Answer» SOLUTION :MASS of OXYGEN in OXIDE `=(35.60-16.50)=19.10g` % of METAL `=(16.50)/(35.60)xx100=46.3` % of oxygen `=(19.10)/(35.60)xx100=53.7`

Discussion

35.	It is found that 0.01 M solution of four sodium salts Na, Nal, NaC and NaD have the following pH values: (i) NaD - 10.0 (ii) NaC = 9.0 (iii) NaB - 8.0 (iv) Na4 - 7.0 Which of the corresponding acids is strongest?
Answer» NAA NaB NaC NAD Solution :`pH = 10`(NaD )showsthat thesolutionin stronglybasic i.e., NaDis asaltofstrongbaseandweakacid SimilarlypH=9and pH = 8refertobasicsolution But pH =7 (NaA) showsthat thesolutionin neutrali.e.,NaA is a saltofstong acidacidstrongbase .

Discussion

36.	KMnO_(4) acts as an oxidising agent in acidic medium. The number of moles of KMnO_(4) that will be needed to react with one mole of sulphide ions in acidic solution is
Answer» `2//5` `3//5` `4//5` `1//5` Solution :`underset("2 mol")(2KMnO_4) + 3H_(2)SO_(4) rarr K_2SO_4 + 2MnSO_(4) + 8H_(2)O + 5S` `therefore `1 MOLE of `S^(2-)` ions will REQUIRE `KMnO_4 = (2)/(5)` moles.

Discussion

37.	It is easier to prepare alkenes by dehydrohalogenation of ___________.
Answer» ALKYL bromide alkyl iodine alkyl chloride alkyl fluoride Answer :B

Discussion

38.	KMnO_(4) acts as an oxidising agent in acidic medium. The number of moles of KMnO_(4) that will be needed to react with one mole of sulphide ions in acidic solution is…..
Answer» `(2)/(5)` `(3)/(5)` `(4)/(5)` `(1)/(5)` Solution :`(2)/(5) MnO_(4)^(-) + S^(2-) + (16)/(5) H^(+) rarr (2)/(5) Mn^(2+) + S + (8)/(5) H_(2)O`

Discussion

39.	It is due to release of _______ from CFCs,CCl_4 depletion of ozone takes place in ________.
Answer» ANSWER :A::C

Discussion

40.	KMnO_4acts as an oxidising agent in
Answer» Acidic MEDIUM only Neutral and acidic medium Neutral and ALKALINE medium Neutral, acidic and fairly BASIC medium Answer :D

Discussion

41.	It is easy to substitute -Cl in 2,4-dinitrochlorobenzene than in chlorobenzene because _________.
Answer» NITRO GROUP donates `E^(-)` at ortho/paraposition. Nitro group withdraws `e^(-)` at metaposition Nitro group donates `e^(-)` META position Nitrogroup donates `e^(-)` at ortho/para position Answer :D

Discussion

42.	KMnO_(4) act as oxidising agent in netural medium. It accept how many electrons to convert MnO_(2).
Answer» 2 3 4 5 Answer :B

Discussion

43.	Why has it been difficult to study the chemistry of radon?
Answer» SOLUTION :RADON is a radioactive element with very SMALL halflife(3.82 DAYS) . HENCE , it isdifficultto studyits chemistry.

Discussion

44.	KMnO_(4) acts as an oxidising agent in
Answer» ACIDIC MEDIUM only Neutral and acidic medium Neutral and ALKALINE medium Neutral, acidic and FAIRLY BASIC medium Answer :D

Discussion

45.	It is desired to prepare 100 ml of a buffer of pH 5.00. Acetic, benzoic and formic acids and their salt are availble for use. Which acid should be used for maximum effectiveness against increase in pH ? What acid-salt ratio should be used ? pK_a values of these acids are : acetic 4.74, benzoic 4.18 and formic 3.68.
Answer» Answer :ACETIC acid, salt-acid MOLAR RATIO 1:8 :1

Discussion

46.	KMnO_(4) acts as an oxidising agent in alkaline medium. When alkaline KMnO_(4)is treated with KI, iodide ion is oxidised to
Answer» `I_(2)` `IO^(-)` `IO_(3)` `IO_(4)^(-)` Solution :`Cr^(3+) : 3D^(3)` `MU = sqrt(n(n+1)) B.M.` ` = sqrt(3(3+2))` ` = 3.87` B.M.

Discussion

47.	It is desired to increase of the volume of a gas by 20% without changing the pressure. To what temprature the gas must be heated if the initial temperature of the gas is 27^(@)C.
Answer» <P> Solution :Let VOLUME at `27^(@)C=V cm^(3)` Final volume `=V+V=(20)/(100) =1.2 V` `therefore V_(1)-v_(1)" "T_(1)=300 K, V_(2)=1.2 V T_(2)=`? At constant `P, (V_(1))/(T_(1))=(V_(2))/(T_(2)) RARR (V)/(300) =(1.2 V)/(12)` `therefore T_(2) =360 K =(360-273)^(@)C=87^(@)C`

Discussion

48.	KMnO_4 act as an oxidising agent in :
Answer» ACIDIC medium Alkaline medium Neutral medium All of the above media Answer :D

Discussion

49.	It is dangerous to leave the car engine running in a closed garage, because it may cause serious pollution due to poisoning by emission of:
Answer» `CO_2` `CO` UNBURNT PETROL `SO_2` ANSWER :B

Discussion

50.	KMnO_(4) (acidic / alkaline ) is not decolurised by
Answer» MOHR salt oxalic acid BENZENE PROPENE Solution :Benzene does not decolourise `KMnO_(4)` (acidic/alkaline) It is due to the delocalization of `pi` - electron in benzene. Mohr.s salt and oxalic and give redox reaction with `KMnO_(4)` . Propene decolorise `KMnO_(4)` due to PRESENCE of `C=C` bond.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

KMnO_(4)gets reduced to

KMnO_(4),and K_(2)Cr_(2)O_(7) are replaced in volumetric analysis by

KMnO_(4)acts as an oxidising agent in acidic medium. The number of moles of KMnO_(4) that will be needed to react with one mole of sulphide ions in acidic solution is:

KMnO_4 will oxidised acetylene to

KMnO_(4) reacts with oxalic acid according to the equation 2MnO_(4)^(-)+5C_(2)O_(4)^(2-)+16H^(+) to 2Mn^(2+)+10CO_(2)+8H_(2)O Here, 20 mL of 0.1 M KMnO_(4) is equivalent to:

KMnO_(4) reacts with KI in basic medium to from I_(2) and MnO_(2). When 250 mL of 0.1 M KI solution is mixed with 250 mL of 0.02 M KMnO_(4) in basic medium, what is the number of moles I_(2)formed ?

KMnO_4 oxidises oxalic acid in acidic medium. The number of CO_2 molecules produced as per the balanced equation is

KMnO_(4) on heating to red hot gives

KMnO_4 oxidises oxalates to ____

KMnO_4 oxidation of which of the following will produce terephthalic acid?

KMnO_(4) on reaction with KOH does not give…

KMnO_4 on heating above 200@C gives:

KMnO_(4) is prepared by

KMnO_4 is prepared by:

KMnO_(4) is iso stuctural with

KMnO_(4) is oxo salt of….

KMnO_(4) in alkaline medium changes to ….

KMnO_(4) is powerful oxidant where it converts into

KMnO_(4) does not act as oxidising agent in the presence of HCI. Why?

KMnO_(4) can be prepared from K_(2)MnO_(4) as per the reaction 3MnO_(4)^(2-) + 2H_(2)O hArr 2MnO_(4)^(2-) + MnO_2 + 4OH^- The reaction can go to completion by removing OH^(-) ions by adding.

KMnO_(4) does not act as oxidising agent in the presence of HCl. Why ?

KMnO_4 can not oxidize

KMnO_(4) can be prepared from K_(2)MnO_(4)as per the reaction : 3MnO_(4)^(2-) + 2H_(2)O hArr2MnO_(4)^(-) + 4OH^(-) Thereaction can go to completion by removing OH^(-) ions by adding

KMnO_(4) can be prepared from K_(2)MnO_(4) as per the reaction, 3MnO_(4)^(2-)+2H_(2)O hArr 2MnO_(4)^(2-)+MnO_(2)+4OH^(-) The reaction can go to completion by removing OH^(-) ions by adding.

KMnO_(4) can be prepared from K_(2)MnO_(4) as per reaction 3MnO_(4)^(2-)+2H_(2)OhArr2MnO_(4)^(-)+MnO_(2)+4OH^(-)

KMnO_(4) can be prepared from K_(2)MnO_(4) as per the reaction 3MnO_(4)^(2-)+2H_(2)O hArr 2MnO_(4)^(-)+MnO_(2)+4OH^(-) The reaction can go to completion by removing OH^(-) ions by adding

KMnO_4 acts as oxidising agent in

KMnO_(4) acts as an oxidizing agent in acidic medium. The number of moles of KMnO_(4) that will be needed to react with one moleof sulphide ions in acidic solution is

KMnO_(4) acts as an oxidising agent in the presence of dil H_2 SO_4. Its equivalent weight is (M is molecular weight)

KMnO_(4) acts as an oxidising agent in alkaline medium. When alkaline KMnO_(4) is treated with KI, iodide ion is oxidised to "…........."

KMnO_(4) acts as an oxidising agent in alkaline medium. When alkaline KMnO_(4) is treated with KI, iodide ion is oxidised to …..

KMnO_(4) acts as an oxidising agent in acidic medium. When alkaline KMnO_4 is treated with KI, iodide ion is oxidised to

KMnO_(4) acts as an oxidising agent in alkaline medium. When alkaline KMnO_(4) is treated with KI, iodide ion is oxidised to……… .

It is found that 16.5 g of metal combine with oxygen to form 35.60 g of metal oxide. Calculate the percentage of metal and oxygen in the compound.

It is found that 0.01 M solution of four sodium salts Na, Nal, NaC and NaD have the following pH values: (i) NaD - 10.0 (ii) NaC = 9.0 (iii) NaB - 8.0 (iv) Na4 - 7.0 Which of the corresponding acids is strongest?

KMnO_(4) acts as an oxidising agent in acidic medium. The number of moles of KMnO_(4) that will be needed to react with one mole of sulphide ions in acidic solution is

It is easier to prepare alkenes by dehydrohalogenation of ___________.

KMnO_(4) acts as an oxidising agent in acidic medium. The number of moles of KMnO_(4) that will be needed to react with one mole of sulphide ions in acidic solution is…..

It is due to release of _______ from CFCs,CCl_4 depletion of ozone takes place in ________.

KMnO_4acts as an oxidising agent in

It is easy to substitute -Cl in 2,4-dinitrochlorobenzene than in chlorobenzene because _________.

KMnO_(4) act as oxidising agent in netural medium. It accept how many electrons to convert MnO_(2).

Why has it been difficult to study the chemistry of radon?

KMnO_(4) acts as an oxidising agent in

KMnO_(4) acts as an oxidising agent in alkaline medium. When alkaline KMnO_(4)is treated with KI, iodide ion is oxidised to

It is desired to increase of the volume of a gas by 20% without changing the pressure. To what temprature the gas must be heated if the initial temperature of the gas is 27^(@)C.

KMnO_4 act as an oxidising agent in :

It is dangerous to leave the car engine running in a closed garage, because it may cause serious pollution due to poisoning by emission of:

KMnO_(4) (acidic / alkaline ) is not decolurised by