94420 + Interview Questions in Chemistry in Class 12 Page 502 InterviewSolution

25051.	The quantity of .^(14)C as well as that of .^(14)CO_(2) present in the atmosphere remains constant. The concentration of .^(14)C in all living organisms remains almost constant during their life time. After their death, .^(14)C is not taken up by them but the content of .^(14)C assimilated begins to decay by emitting beta- particles, with half-life period of 5568 years. The decay rate at the time of death of plant is 16.1counts per minute per gram of carbon. Hence, by measuring the decay rate of the dead matter, the age of matter can be calculated , e.g. if decay rate of sample of wood is found to be N distengrations per minute per gram of carbon after t years, then N=N_(0)e^(-lambda t) where lambda= disntegration constant and N_(0)= number of disntegrations per minute per gram when the plant had just died. In a dead plant, the decay rate will be
Answer» higer than in a living PLANT lower than in a living plant the ratio of `.^(14)C//.^(12)C` which will increase in a dead plant as COMPARED to a living plant NONE of the above Answer :B

Discussion

25052.	The quantity electricity needed separately for the electrolysis of 1 M solution of ZnSO_(4), AlCl_(3) and AgNO_(3) completely is in the ratio of :
Answer» `2:3:1` `2:1:1` `2:1:3` `2:2:1` Solution :(a) `Zn^(2+)+underset(2F)2e^(-) to underset(1mol)(Zn)` `AL^(3+)+underset(3F)3e^(-) to underset(1mol)(Al)` `Ag^(+)+underset(1F)e^(-) to underset(1 MOL)(Ag)` The NUMBER of FARADAYS needed are in the ratio : `2F:3F:1F "or" 2:3:1`.

Discussion

25053.	The quantify of electricity required to liberate 112 cm^(3) of hydrogen at STP from acidified water is
Answer» 0.1 Faraday 06500 Coulombs 965 Coulombs 1 Faraday Solution :2g of `H_(2)` at S.T.P liberated `= 22400 cm^(3)` 1 G of `H_(2)` at S.T.P liberated = `11200 cm^(3)` For liberation `11200 cm^(3) H_(2)` at S.T.P. required = 96500C For liberation `112 cm^(3) H_(2)` at S.T.P required `= (96500 XX 112)/(11200) = 965C`

Discussion

25054.	The quantigy of electricity required to liberate 1 gram equivalent of an element is at
Answer» 1 AMPERE 96500 amperes 96500 coulombs 96500 faradays Solution :Equivalent WEIGHT of substance is OBTAINED by passing 96,500 C or 1 F electricity .

Discussion

25055.	The quality of soap is described interms of .................... and the .................... quantity in the soap better is its quality
Answer» SOLUTION :TFM,TFM

Discussion

25056.	The qualitative order of Debrogile wavelegnth for electron, proton and alpha particle is lambda_(e) gt lambda_(P) gt lambda_(alpha) if
Answer» If KINETIC energy is same for all particles If the acelerating POTENTIAL difference 'V' is same for all the PARTICLE (from rest) If velocities are same for all particles None of above Answer :A, B, C

Discussion

25057.	The qualitative analysis to the salt solution addition of reagents NH_(4)CI+NH_(4)OH and ammonium carbonate give precipitate in precipitate the oxidation state of anion (only magnitude)
Answer» SOLUTION :`BA^(+2), SR^(+2), CA^(+2)`

Discussion

25058.	The pyrolusite ore contains:
Answer» Fe Al Mn Cu Answer :C

Discussion

25059.	The pyrolusiteore contains
Answer» Cu AL Mn FE Answer :C

Discussion

25060.	The pyrimidine bases present in DNA are :
Answer» CYTOSINE and guanine Cytosine and thymine Cytosine and uracil Cytosine and ADENINE. ANSWER :B

Discussion

25061.	The pyrimidinebase presentin DNA are ………. .
Answer» Cytosineand ADENINE Cytosineand GUANINE Cytosine and Thiamine Cytosineand URACIL ANSWER :C

Discussion

25062.	The pyramidal inversion from one invertomer of chiral tetrahedral amine to another takes place via
Answer» Carbocationic intermediate Anionic NITROGEN intermediate Cationic nitrogen intermediate PLANAR nitrogen Solution :Planar nitrogen

Discussion

25063.	The pyknometer density of NaCl crystal is 2.165 xx 10^(3) kg m^(-3) while its X -rays density is 2.178 xx 10^(3) kg m^(-3). The fraction of the unoccupied sites in NaCl crystal is :
Answer» 5.96 `5.96 XX 10^(-2)` `0.596` `5.96 xx 10^(-3)` ANSWER :D

Discussion

25064.	The putial pressure of ethane over a saturated solution containing 6.56 xx 10^(-2) g of ethane is 1 bar.if the solution contains 5.0 xx 10^(-2) g of ethane, then what will be the partial pressure of the gas ?
Answer» Solution :Let the Henry.s law constant be `K_(H)` and no. of MOLES of solvent be M. Partial pressure of ethane = `K_(H)` x mole fraction of ethane ` I = K_(H) XX (6.56 xx 10^(-2))/((30)/(M)) ` `K_(H) = (M xx 30)/(6.56 xx 10^(-2))` Now the partial pressure of ethane containing 5.0 `xx 10^(-2)` will be ` = (M xx 30)/(6.56 xx 10^(-2)) xx (5.0 xx 10^(-2))/(30 xx M)` = 0.762 BAR.

Discussion

25065.	The purpose of smelting of an ore is :
Answer» To oxidise it To reduce it To SEPARATE volatile impurities To obtain an alloy Answer :C

Discussion

25066.	The purpose of salt bridge is to:
Answer» Allow electron flow All CHEMICAL REDUCTION Allow chemical OXIDATION Allow ion flow Solution :ion flow only

Discussion

25067.	The purpose of addition of KF to HF in the preparation of Fluorine by electrolysis is
Answer» to INCREASE the conductance of HF to DECREASE the oxidation POTENTIAL of HF to lower the solubility of HF to increase the MELTING point of HF Answer :A

Discussion

25068.	The purple colour of KMnO_4 is due to ___
Answer» d-d transition charge transfer f-f transition none of these Answer :B

Discussion

25069.	The purple colour of KMnO_(4) is due to
Answer» Charge TRANSFER d-d transition f-f transition d-f transition Solution :The permanganate ion has an INTENSE purple COLOUR `Mn(+VII)` has a `d^(0)` configuration. So the colour arises from charge transfer and not from d-d spectra.

Discussion

25070.	The purity of blistered copper is _____.
Answer» SOLUTION :`98%`

Discussion

25071.	The purity of blistered copper is _____ .
Answer» SOLUTION :`98%`

Discussion

25072.	The purity of an organic compound is best determined by :
Answer» Density Molecular weight Colour Melting point Answer :D

Discussion

25073.	The purine heterocycle occurs mainly in the structure of DNA. Identify number of N atoms having localised lone pair of electron.
Answer» SOLUTION :

Discussion

25074.	The purine bases present in both DNA and RNA are :
Answer» GUANINE and adenine Guanine and URACIL Adenine and thymine Cytosine and uracil ANSWER :A

Discussion

25075.	The purine base present in RNA is
Answer» Guanine Thymine Cytosine Uracil Answer :D

Discussion

25076.	The purine base present in DNA is :
Answer» Adenine Cytosine Uracil Thymine Answer :A

Discussion

25077.	The purification of a organic compound is varified with
Answer» Melting point Molecular weight Density Solubility in water Solution :Sharp m.p. (in CASE of solids) and BOILING point ( in case of liquids) are used as CRITERIA for PURITY because their DETERMINATION is feasible in thelaboratory.

Discussion

25078.	The purification of the colloidal particles from crystalloid dimensions through semipermeable membrane is known as:
Answer» Coagulation Dialysis Ultrafiltration Peptization Answer :B

Discussion

25079.	The purification of colloidal solution could be
Answer» ULTRA filtration Dialysis Electrodialysis All of these Answer :D

Discussion

25080.	The purification method used for mineral Al_2O_3. 2H_2O is :
Answer» FROTH floatation Lizuation Leaching Magnetic separation Answer :C

Discussion

25081.	The purestform ofiron is preparedbyoxidisingimpuritiesfrom castiron inareverberatoryfurnace.Whichiron ore is usedtolinethe furnace ?Explainby givingreaction.
Answer» Solution :Thereverberatoryfurnaceis linedinsidewithhaematite.It suppliesthenecessaryoxygen requiredfor oxidationofimpurities ofCto`CO _ 2` S to` S O_2`,PTO`P_ 4 O_(10) ` ,MntoMnO ,etc. `Fe_2O_3(s)+3C(s)to2Fe(s)+3 CO(g) ` `2Fe_2O _ 3 (s)+3S(s)TO4 FE (s)+3SO_2 (g) `

Discussion

25082.	The purest form of iron is prepared by oxidising impurities from cast iron in a reverberatory furnace. Which iron ore is used to line the furnace ? Explain by giving reaction.
Answer» Solution :The lining of FURNACE is done by Haematite `(Fe_2O_3)` which oxidises CARBON to `CO`. ` Fe_2O_3 + 3C to 2Fe + 2CO` The impurities of sulphur, silicon and PHOSPHORUS are oxidised to `SO_2, SiO_2 and P_4O_10` respectively `SO_2` ESCAPES out while `SiO_2` and `P_4O_10` are REMOVED as slag.

Discussion

25083.	The purest form of iron is
Answer» Pig iron WHITE cast iron Malleable iron GREY cast iron Solution :Wrought iron (malleable iron) is PUREST FORM of iron.

Discussion

25084.	The purest form of iron is _________.
Answer» PIG iron wrought iron steel All of these Answer :B

Discussion

25085.	The purest form of commercial iron is
Answer» PIG IRON CAST iron Wrought iron Pig iron and cast iron Answer :C

Discussion

25086.	The purest form of commercial iron is :
Answer» CAST IRON Wrought iron Pig iron NONE of these ANSWER :B

Discussion

25087.	The pure zince carbonate is prepared by addition of the following reagent to a zinc sulphate solution
Answer» Sodium carbonate Calcium carbonate Sodium bicarbonate Sodium hydroxide `+` Sodium carbonate Solution :Addition of `Na_(2)CO_(3)` gives ZINC carbonate and zinc hydroxide . `NaHCO_(3)` is an ACID salt.

Discussion

25088.	The purest form of coal is
Answer» PEAT ANTHRACITE Bituminous Lignite SOLUTION :The PUREST form of coal is anthracite, because it has highest percentage of carbon

Discussion

25089.	The purest form of carbon is :
Answer» BITUMINOUS coal Coal-tar Coal gas Diamond Answer :D

Discussion

25090.	The pure ethanol is obtained by
Answer» MEMBRANE TECHNOLOGY Fermentation Acid CATALYST HYDRATION of alkenes Hydroboration OXIDATION reaction Solution :Membrane technology

Discussion

25091.	The pure crystalline substance on being heated gradually first forms a turbid liquid at constant temperature and still at higher temperature turbidity completely disappears. The behaviour is a characteristics of substance forming:
Answer» ALLOTROPIC CRYSTAL LIQUID crystal Isomeric crystals Isomorphous crystals Answer :B

Discussion

25092.	The pupose of additio of KF to HF in the preparation of F_(2) by electrolysis is
Answer» to INCREASES the CONDUCTANCE of HF to decreases the OXDIATION potential of HF to increasses the F conecentration To decreases the KF or concentration Answer :A

Discussion

25093.	The pure crystalline substance on being heated gradually first forms a turbid liquid at constant temperature and still at higher temperature turbidity completely disappears. The behaviour is a characteristic of substance forming.
Answer» ALLOTROPIC crystals LIQUID crystals Isomeric crystals isomorphous crystals. Solution :It is the PROPERTY of liquid CRYSTAL.

Discussion

25094.	The pseudohalogen amongst the following is-
Answer» NO CO `Cl_2` `C_2N_2` ANSWER :D

Discussion

25095.	The Prussium blue colour obtained in the Lassaigne's test forn nitrogen is due to the formulaof
Answer» Iron (II) hexacyanoferrate (III) Iron (III) hexacyanoferrate (II) Iron (III) hexacyanoferrate (III) Iron (II) hexacyanoferrate (II) Solution :The chemistry of the Lassaigne's test of nitrogen is `underset("compound")underset(" CROM organic")(Na+C+N)OVERSET(Delta)rarrNaCN` `2NaCN + FeSO_(4)rarr Fe(CN)_(2) + Na_(2)SO_(4)` `Fe(CN)_(2)+4NaCNrarrunderset(" Sod.FERROCYANIDE")(Na_(4)[Fe(CN)_(6)]` `3Na_(4)[Fe(CN)_(6)]+4Fe_(3)^(+)rarr underset(" Porusian blue")underset(" Ferric ferrocyanide")(Fe_(4)[Fe(CN)_(6)]_(3)+12Na^(+))`

Discussion

25096.	The prussian blue colour obtained during the test of nitrogen by Lassiagne'stest is due to the formation of
Answer» `Fe_(4)[Fe(CN)_(6)]_(3)` `Na_(3)[Fe(CN)_(6)]` `Fe(CN)_(3)` `Na_(4)(FECN)_(5)NOS]` Solution :N//A

Discussion

25097.	The prussian blue colour obtained during the test of nitrogen by Lassaigne's test is due to the formation of:
Answer» `Fe[Fe(CN)_(6)]_(3)` `Na_(3)[Fe(CN)_(6)]` `Fe(CN)_(3)` `Na_(4)[Fe(CN)_(5)NOS]` SOLUTION :`NH_(4)[Fe(CN)_(5)NO_(5)]` BLUE

Discussion

25098.	The prussian blue colour obtained during the test of nitrogen by Lassaigne's test is due the formation of :
Answer» `Fe_(4)[Fe(CN)_(6)]_(3)` `Na_(3)[Fe(CN)_(6)]` `Fe(CN)_(3)` `Na_[Fe(CN)_(5)NOS]` SOLUTION :N//A

Discussion

25099.	The Proudct formedin followingreactionisCH_(3) - overset(NO_(2))overset(\|)(CH)-CH_(3) overset(H_(3)O^(+))to ?
Answer» `CH_(3)-CH_(2) - CHO` `CH_(3) - overset(CH_(3))overset(\|)(CH) - COOH` `CH_(3) - overset(CH_(3))overset(\|)(C) =O` `CH_(3) - overset(CH_(3))overset(\|)(CH) - OH` Solution :Secondarynitroalkaneon acidhydrolysisgivesketone. `2CH_(3) -underset(NO_(2))underset(\|)(CH) - CH_(3) + H. OHoverset(H^(+))to2CH_(3) underset(O)underset(\|\|) (C) - CH_(3) + N_(2)O + 2H_(2) O`

Discussion

25100.	The prussian blue colour in the test of nitrogen by Lassagine's solution is due to :
Answer» `Na_(4)[Fe(CN)_(6)]` `Fe(SCN)_(3)` `Na_(4)[Fe(CN)_(5)NOS]` `Fe_(4)[Fe(CN)_(6)]_(3)` ANSWER :D

Discussion

Explore topic-wise InterviewSolutions in .

The quantity electricity needed separately for the electrolysis of 1 M solution of ZnSO_(4), AlCl_(3) and AgNO_(3) completely is in the ratio of :

The quantify of electricity required to liberate 112 cm^(3) of hydrogen at STP from acidified water is

The quantigy of electricity required to liberate 1 gram equivalent of an element is at

The quality of soap is described interms of .................... and the .................... quantity in the soap better is its quality

The qualitative order of Debrogile wavelegnth for electron, proton and alpha particle is lambda_(e) gt lambda_(P) gt lambda_(alpha) if

The qualitative analysis to the salt solution addition of reagents NH_(4)CI+NH_(4)OH and ammonium carbonate give precipitate in precipitate the oxidation state of anion (only magnitude)

The pyrolusite ore contains:

The pyrolusiteore contains

The pyrimidine bases present in DNA are :

The pyrimidinebase presentin DNA are ………. .

The pyramidal inversion from one invertomer of chiral tetrahedral amine to another takes place via

The pyknometer density of NaCl crystal is 2.165 xx 10^(3) kg m^(-3) while its X -rays density is 2.178 xx 10^(3) kg m^(-3). The fraction of the unoccupied sites in NaCl crystal is :

The putial pressure of ethane over a saturated solution containing 6.56 xx 10^(-2) g of ethane is 1 bar.if the solution contains 5.0 xx 10^(-2) g of ethane, then what will be the partial pressure of the gas ?

The purpose of smelting of an ore is :

The purpose of salt bridge is to:

The purpose of addition of KF to HF in the preparation of Fluorine by electrolysis is

The purple colour of KMnO_4 is due to ___

The purple colour of KMnO_(4) is due to

The purity of blistered copper is _____.

The purity of blistered copper is _____ .

The purity of an organic compound is best determined by :

The purine heterocycle occurs mainly in the structure of DNA. Identify number of N atoms having localised lone pair of electron.

The purine bases present in both DNA and RNA are :

The purine base present in RNA is

The purine base present in DNA is :

The purification of a organic compound is varified with

The purification of the colloidal particles from crystalloid dimensions through semipermeable membrane is known as:

The purification of colloidal solution could be

The purification method used for mineral Al_2O_3. 2H_2O is :

The purestform ofiron is preparedbyoxidisingimpuritiesfrom castiron inareverberatoryfurnace.Whichiron ore is usedtolinethe furnace ?Explainby givingreaction.

The purest form of iron is prepared by oxidising impurities from cast iron in a reverberatory furnace. Which iron ore is used to line the furnace ? Explain by giving reaction.

The purest form of iron is

The purest form of iron is _________.

The purest form of commercial iron is

The purest form of commercial iron is :

The pure zince carbonate is prepared by addition of the following reagent to a zinc sulphate solution

The purest form of coal is

The purest form of carbon is :

The pure ethanol is obtained by

The pure crystalline substance on being heated gradually first forms a turbid liquid at constant temperature and still at higher temperature turbidity completely disappears. The behaviour is a characteristics of substance forming:

The pupose of additio of KF to HF in the preparation of F_(2) by electrolysis is

The pure crystalline substance on being heated gradually first forms a turbid liquid at constant temperature and still at higher temperature turbidity completely disappears. The behaviour is a characteristic of substance forming.

The pseudohalogen amongst the following is-

The Prussium blue colour obtained in the Lassaigne's test forn nitrogen is due to the formulaof

The prussian blue colour obtained during the test of nitrogen by Lassiagne'stest is due to the formation of

The prussian blue colour obtained during the test of nitrogen by Lassaigne's test is due to the formation of:

The prussian blue colour obtained during the test of nitrogen by Lassaigne's test is due the formation of :

The Proudct formedin followingreactionisCH_(3) - overset(NO_(2))overset(|)(CH)-CH_(3) overset(H_(3)O^(+))to ?

The prussian blue colour in the test of nitrogen by Lassagine's solution is due to :