94420 + Interview Questions in Chemistry in Class 12

1.	Pyrolusite is the main ore of manganese in which it is present asIts Mn content is determined by reducing it under acidic condition to Mn^(2+)with the help of oxalate (C_(2)O_(4)^(2-)) ion which in turn gets oxidized to CO_(2) The analytical determination is carried out by adding a known excess volume of (C_(2)O_(4)^(2-)) solution to a suspension of the pyrolusite and digesting the mixture on a hot water bath until all the MnO_(2) has been reduced. The excess unreacted oxalate solution is then titrated with standardized KMnO_(4) solution. Thereby Mn content of ore can be calculated. KMnO_(4)solution is also standardized under acidic condition against oxalate ion wherein MnO_(4)^(-) ion is reduced to Mn^(2+) and (C_(2)O_(4)^(2-)) ion is oxidized to CO_(2)Q If a student prepared a standard solution of Na_(2)C_(2)O_(4) by dissolving 3.2 g of dry anhydrous salt into distilled water and making the solution upto 500 mL. The Normality of oxalate solution is
Answer» 0.085 0.096 0.054 0.032 Solution :`C_(2)O_(4)^(2-)to2CO_(2)+2e^(-)` `THEREFORE E_(Na_(2)C_(2)O_(4))=(134)/(2)=67g`m Normality=`(3.2/67)/(500)xx1000`=0.096N

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2.	Pyroligneous acid (one of the fraction of destructive distillation of wood), does not contain
Answer» STEARIC acid Acetic acid Methanol Acetone SOLUTION :PYROLIGNEOUS aicd does not CONTAIN stearic acid.

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3.	Pyroligeneous acid obtained during destructive distillation of wood contains :
Answer» ACETONE and methyl ALCOHOL methyl alcohol and ETHYL alcohol acetone and ACETIC ACID methyl alcohol, acetone and acetic acid Answer :D

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4.	pyroligneous acid contains:
Answer» `2%` ACETIC ACID `50%` acetic acid `10%` acetic acid `20%` acetic acid Answer :C

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5.	Pyroligneous acid cntains :
Answer» `CH_3COOH(10%),CH_3OH(2.5%)CH_3COCH_3(0.5%)` `C_2H_5OH(10%),CH_3OH(2.5%),CH_3COCH_3(0.5%)` `CH_3COCH_3(10%),C_2H_5OH(2.5%),CH_3OH(0.5%)` None Answer :A

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6.	Pyridinium chlorochromate (PCC) is a selective oxidising agent to oxidise a 1^@ alcohol to corresponding aldehyde.
Answer» ANSWER :T

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7.	Pyridoxine is _____.
Answer» VITAMIN `B_(6)` vitamin `B_(7)` vitamin `B_(9)` vitamin `B_(5)` Solution :vitamin `B_(5)`

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8.	Pyridine like benzene, has six pi-electrons in delocalized pi - orbitals, but unlike benzene the orbitals will be deformed are more attractedtowardsthe nitrogen atom because of its high elecrtonegativity. This is reflected in the dipole of pyridine which has the negative end on Nand the positive end on the nucleus. Pyridine is thus reffered to as a pi - deficient hetrocycle. By analogy with a benzene ring that carries an electron-withdrawing substituent, NO_(2) one would expect it to be deactivated towards electrophilic attack with the help of pi delocalized molecular orbital. We can compare the respective properties of benzene, pyridine, pyrrole, furan and thiophene, which very frequently give aromatic electrophilic and nucleophilic substitution reactions in different positions. The simplest of six membered heterocyclic nitrogen compound is
Answer» pyrrole quinoine pyridine purine Answer :C

Discussion

9.	Pyridine is mixed with aqueous solution of NiSO_(4), NaNO_(2) solution is then added to mixture to get dark blue precipitate 'A'. Analyse show that A does not contain any SO_(4)^(2-) ion but produce three ions per molecule A is
Answer» `[Ni(Py)_(2)[NO_(2))_(2)]` `[Ni(Py)_(4)](NO_(2))_(2)` `[Ni(Py)_(3)NO_(2)]_(2)SO_(4)` `[Ni(Py)_(4)]SO_(4)` ANSWER :B

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10.	Pyridine is more basic than pyrrole. Which of these of following statememt explain this fact?
Answer» In pyrrole lone pair is involved in armaticity, in pyridine lone pair is not involved in aromaticity it is FREE for donation Conjugated acid of pyridine remains AROMATIC but pyrrole does not REMAIN aromatic. Homolytic bond fission TAKES place in NON polar solvents `+M` power of pyrrolel is greater than pyridine Solution :N/A

Discussion

11.	Pyrexglassis obainedbyfusingtogether_____.
Answer» 60 to 80%`Al_(2)O_(3)` 10to25%`SiO_(2)` andramininf amountof `B_(2)O_(3)` 60to 80%`B_(2)O_(3)`, 10to 25%`Al_(2) O_(3) and` remainingamountof `SIO_(2)` 60to80 %`SiO_(2), 10` to`25%B_(2)O_(3) ` andremainingamountof `Al_(2) O_(3) ` 60to 80%`SiO_(2), 10"to "25% Al_(2) O_3` andreamingamountof ` B_(2)O_(3) ` Answer :C

Discussion

12.	Pyridine is less basic than triethylamine because
Answer» Pyridine has aromatic character Nitrogen in pyridine is `sp^2` hybridized Pyridine is a CYCLIC system In pyridine, lone pair of nitrogen is delocalized Solution :BASICITY of amines is due to availability of an UNSHARED pair (lone pair) of electrons on nitrogen . This lone pair of electrons is AVAILABLE for the formation of a new bond with a proton or Lewis acid . Pyridine is less basic than triethylamine because lone pair of ELECTRON in nitrogen in pyridine is delocalised.

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13.	'Pyrene' is the trade name of ....... which is used as fire extinguisher
Answer» `CO_2` ` CHCl_3` ` C C l_4` ` CH_5 CL _2` ANSWER :C

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14.	Pyrene is the trade name of â€¦â€¦.. when used as fire extinguisher
Answer» `C Cl_(4)` `CHCl_(3)` `CO_(2)` `CH_(2)Cl_(2)` Answer :A

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15.	Pyrene (a fire extinguisher ) is :
Answer» `SiCl_4` `C Cl_4` `GeCl_4` `SbCl_5` ANSWER :B

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16.	p_(y)-orbital can not form pi -bond by lateral overlap with :
Answer» <P>`d_(XZ)`- ORBITAL `d_(x^(2)-y^(2))`-ORBITALS `d_(xy)`-orbital `p_(z)` -orbital Answer :A::B::D

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17.	Pyranose structure of glucose is
Answer» HEXAGONAL PENTAGONAL LINEAR TETRAHEDRAL ANSWER :D

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18.	PVC, polythene, LDPE, cellulose, HDPE, bakelite
Answer» SOLUTION :Cellulose. It is a NATURAL POLYMER WHEREAS others are synthetic polymers.

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19.	PVC is produced by the polymerisation of :
Answer» VINYL acetate Allyl chloride Vinyl chloride Ethene Answer :C

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20.	_______ is used to make non-stick cookware.
Answer» PVC Teflon Fluon None Solution :POLYTETRAFLUOROETHYLENE

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21.	PVC is used for
Answer» Manufactured of cosmetics Manufacture of tyres MANUFACTURES of NONSTICK pans Manufacture of PLASTICS pipes ANSWER :D

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22.	PVC is prepared by the polymerisation of
Answer» ETHYLENE 1-chloropropene Propene 1-chloroethene Solution :PVC is POLYVINYL chlorde, a polymer of vinyl CHLORIDE. `UNDERSET("1-chloroethene")(nCH_(2)=CH.Cl)overset("Polymerisation")tounderset(PVC)([-CH_(2)-overset(Cl)overset(\|)(CH)-])_(n)`

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23.	PVC is of which type polymer ?
Answer» BRANCH Cross linked LINEAR NONE of these Solution :Branch

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24.	PVC is obtained by polymerization of
Answer» `CH_2=CH_2` `CH_3-CH=CH_2` `CH_2=CH-Cl` `C_6H_5-CH=CH_2` ANSWER :C

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25.	Which is naturally occurring polymer?
Answer» SOLUTION :PROTEIN is a NATURALLY OCCURING POLYMER.

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26.	PVC is a polymer of _____.
Answer» ethylene tetrafluoroethene chloroethene none Solution :PROTEIN is a NATURALLY OCCURING POLYMER.

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27.	PVC is an example of
Answer» theremosetting thermoplastic elastic FIBRE. ANSWER :B

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28.	PVC is a polymer of:
Answer» `CH_2=CH_2` `CICH_2-CH_2CI` `CH_2=CHCI` `CI-C-=C-CI` ANSWER :A

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29.	PVC, bakelite and polythene are plastics Name the monometer units of PVC and bakelite .
Answer» Solution :Monomers of PVC: vinyl chloride, `CH_2=CH-Cl` MONOMER of bakelite:PHENOL `(C_6H_5OH) and Formaldehyde (HCHO)

Discussion

30.	PVC, bakelite and polythene are plastics. Classify the above plastics into thermoplastics and thermosetting plastics.
Answer» SOLUTION :Thermoplastics-PVC, POLYTHENE. Thermostting PLASTICS- BAKELITE

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31.	PVC.
Answer» SOLUTION :It is used in the MANUFACTURE of SHEETS, waterpipes hand BAGS, ETC.

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32.	Purpose of hydrogen -oxygen fuel cell is to
Answer» GENERATE heat Ccreate potential difference Produce high purity water Remove adsorbed oxygen from ELECTRODE surface Answer :B

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33.	Purk alkyl bromide is formed from bromination of which alkane ?
Answer» iso-butane ethane propane 2-methyl butane Answer :B

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34.	Purple of cassius is colloidal sol of :
Answer» Silver GOLD Copper PLATINUM. ANSWER :B

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35.	Purple of cassius is a colloidal sol of
Answer» SILVER platium gold IRON Answer :C

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36.	Purity of butter is determined in terms of:
Answer» SAPONIFICATION VALUE Iodine value ACETYL value Rechert-Meissl value ANSWER :D

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37.	Purity of ether before using it as anaesthetic agent is tested by :
Answer» KI + STARCH `CuSO_4` `H_2SO_4` None Answer :A

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38.	Purine without ketonic group is
Answer» ADENINE adenosine cytidine thymidine ANSWER :A

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39.	Purification or Refining of metals : Metals obtained by reduction processes still contain some objectionable impurities and have to be refined Numerous techniques are available , including the following : Physical methods:These methods include the following processes : (I) Liquation process (II)Fractional distillation process (III)Zone refining method(IV)Chromatographic methods Chemicalmethods : These methods include the following methods : (I)Oxidative refining(II)Poling process (III)Electrolytic refining(IV)Vapour phase refining Now answer the following questions . Select the correct statements :
Answer» Q,r,s p,q,r p,q,s None of these Solution :(p)Liquation process is used for purification of impure tin and zinc METALS as the impurities present have higher MELTING point than the METAL itself. (s)Cupellation involves removal of Pb impurity from Ag metal.

Discussion

40.	Purine derivative among the following bases is
Answer» cytosine GUANINE uracil thymine Solution :Guanine is PURINE DERIVATIVE.

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41.	Purification or Refining of metals : Metals obtained by reduction processes still contain some objectionable impurities and have to be refined Numerous techniques are available , including the following : Physical methods:These methods include the following processes : (I) Liquation process(II)Fractional distillation process (III)Zone refining method(IV)Chromatographic methods Chemicalmethods : These methods include the following methods : (I)Oxidative refining (II)Poling process (III)Electrolytic refining(IV)Vapour phase refining Now answer the following questions . Select the INCORRECT statement :
Answer» Poling process used in purification of COPPER & tin involves reduction of impurities present Electrolytic refining is DONE for reactive metal Al as well as less reactive metal Cu. Refining of metal obtained from cassiterite ore involves removal of copper impurity Vapour PHASE refining involves oxidation of metal to be refined, followed by its reduction at a HIGHER temperature. Solution :Refining of metal obtained from cassiterite ore involves removal of iron impurity.

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42.	Purine and pyrimidine bases present in both DNA and RNA are
Answer» URACIL thymine CYTOSINE ADENINE Answer :C,D

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43.	Purification of Nickel by ............... Process involves formation .................. Which yields 99.5% pure Nickel on decomposition.
Answer» ANSWER :MOND's, `[NI(CO)_(4)]`

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44.	Purification of silicon element used in semiconductors is done by :
Answer» ZONE REFINING HEATING FROTH floatation Heating in vaccum Answer :A

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45.	Purification of colloids is done by:
Answer» HEATING PRECIPITATION coagulation dalysis. Answer :D

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46.	Purification of blood is carried out by....
Answer» coagulation DIALYSIS electroosmosis ultrafiltration SOLUTION :dialysis

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47.	Purification of bone black is carried out by
Answer» `CH_(3)COOH` `H_(2)SO_(3)` `HNO_(3)` `HCI` ANSWER :D

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48.	Purification of aluminium done by electrolytic refining is known as
Answer» Serpeck's PROCESS HALL's process Baeyer's process HOOP's process Answer :D

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49.	Purification of alumina by electrorefining is known as :
Answer» HALL's PROCESS FROTH flatation process Baeyer's process Hoope's process Solution :PURIFICATION of alumnium is done by HOOP's process.

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50.	Purification of aluminium by electrolytic refining is carried out by
Answer» Hoope PROCESS HALL process BAEYER process Serperckprocess ANSWER :A

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Pyroligneous acid (one of the fraction of destructive distillation of wood), does not contain

Pyroligeneous acid obtained during destructive distillation of wood contains :

pyroligneous acid contains:

Pyroligneous acid cntains :

Pyridinium chlorochromate (PCC) is a selective oxidising agent to oxidise a 1^@ alcohol to corresponding aldehyde.

Pyridoxine is _____.

Pyridine is mixed with aqueous solution of NiSO_(4), NaNO_(2) solution is then added to mixture to get dark blue precipitate 'A'. Analyse show that A does not contain any SO_(4)^(2-) ion but produce three ions per molecule A is

Pyridine is more basic than pyrrole. Which of these of following statememt explain this fact?

Pyrexglassis obainedbyfusingtogether_____.

Pyridine is less basic than triethylamine because

'Pyrene' is the trade name of ....... which is used as fire extinguisher

Pyrene is the trade name of â€¦â€¦.. when used as fire extinguisher

Pyrene (a fire extinguisher ) is :

p_(y)-orbital can not form pi -bond by lateral overlap with :

Pyranose structure of glucose is

PVC, polythene, LDPE, cellulose, HDPE, bakelite

PVC is produced by the polymerisation of :

_______ is used to make non-stick cookware.

PVC is used for

PVC is prepared by the polymerisation of

PVC is of which type polymer ?

PVC is obtained by polymerization of

Which is naturally occurring polymer?

PVC is a polymer of _____.

PVC is an example of

PVC is a polymer of:

PVC, bakelite and polythene are plastics Name the monometer units of PVC and bakelite .

PVC, bakelite and polythene are plastics. Classify the above plastics into thermoplastics and thermosetting plastics.

PVC.

Purpose of hydrogen -oxygen fuel cell is to

Purk alkyl bromide is formed from bromination of which alkane ?

Purple of cassius is colloidal sol of :

Purple of cassius is a colloidal sol of

Purity of butter is determined in terms of:

Purity of ether before using it as anaesthetic agent is tested by :

Purine without ketonic group is

Purine derivative among the following bases is

Purine and pyrimidine bases present in both DNA and RNA are

Purification of Nickel by ............... Process involves formation .................. Which yields 99.5% pure Nickel on decomposition.

Purification of silicon element used in semiconductors is done by :

Purification of colloids is done by:

Purification of blood is carried out by....

Purification of bone black is carried out by

Purification of aluminium done by electrolytic refining is known as

Purification of alumina by electrorefining is known as :

Purification of aluminium by electrolytic refining is carried out by