94420 + Interview Questions in Chemistry in Class 12 Page 1760 InterviewSolution

87951.	A qha-regia is a mixtue of
Answer» `1:3` mixture of CON HCL & con `HNO` `3:1` mixture of con HCl & con `HNO_(3)` `1:3` mixture of con HCl & con `H_(2)SO_(4)` 3`:1` mixture of con `H_(2)SO_(4)` & con HCl Solution :3 parts HCl and 1 PART `HNO_(3)` mixture is called aqua regia.

Discussion

87952.	A purple coloured solution is made alkaline with KOH and is treated with KI forming potassium iodate. The same solution is acidified with H_(2) SO_(4) and again it is treated with Kl. However this time instead of potassium iodate, iodine gas is released. The purple coloured solution is of
Answer» `K_(2)Cr_(2)O_(7)` `K_(2)Cr_(2)O_(4)` `KMnO_(4)` `K_(2)MnO_(4)` Answer :C

Discussion

87953.	A pure substance which contains only one type of atoms is called:
Answer» an ELEMENT a compound a solid a liquid. ANSWER :A::B::C

Discussion

87954.	A pure substance can only be:
Answer» a compound an ELEMENT an element or a compound. a heterogeneous MIXTURE. ANSWER :C

Discussion

87955.	A: Pure silver is obtained by electrolysis of AgNO_3 solution R: In electrolysis impure silver is taken as cathode and pure silver is taken as anode.
Answer» If both ASSERTION & Reason are true and the reason is the CORRECT explanation of the assertion, then mark (1). If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2) If Assertion is true statement but Reason is FALSE, then mark If both Assertion and Reason are false statements, then mark (4) Answer :C

Discussion

87956.	A pure sample of 2-chlorobutane shows rotation of PPL by 30º in standard conditions. When above sample is made impure by mixing its opposite form, so that the composition of the mixture become 87.5% d-form and 12.5% l-form, then what will be the observed rotation for the mixture.
Answer» `-22.5^(@)` `+22.5^(@)` `+7.5^(@)` `-7.5^(@)` ANSWER :B

Discussion

87957.	A pure dextrorodtory monocarboxyhe acid is treated with racemic mixture of an alcohol contaning one chiral carbon. The ester formed will be
Answer» pure DEXTROROTATORY RACEMIC mixture meso compound optically active mixture containing EXCESS dextrorotatory compound Answer :D

Discussion

87958.	A Pt complex of NH3 and chlorine produces four ions per molecule in the solution is :-
Answer» `[PT(NH_(3))_(4)Cl_(2)]Cl_(2)` `[Pt(NH_(3))_(6)]Cl` `[Pt(NH_(3))_(2)]Cl_(4)` `[Pt(NH_(3))_(5)Cl]Cl_(3)` ANSWER :D

Discussion

87959.	(A) Pure chloroform does not give precipitate with AgNO_3 solution. (R) CHCI_3 is covalent compound.
Answer» Both A & R are TRUE, R is the correct EXPLANATION of A Both A & R are true, R is not correct explanation of A A is true, R is false A is false, R is true Answer :A

Discussion

87960.	A Pt complex of ammonia and chlorine produces four ions per molecule in the solution is
Answer» `[PT(NH_(3))_(5)CL]Cl_(3)` `[Pt(NH_(3))_(6)]Cl_(4)` `[Pt(NH_(3))_(2)Cl_(4)]` `[Pt(NH_(3))_(4)Cl_(2)]Cl_(2)` Answer :A

Discussion

87961.	(A) Protons are better projectiles than neutrons. (R ) The neutrons being neutral do not experience repulsion from positively charged nucleus.
Answer» If both (A) and (R ) are CORRECT and (R ) is the correct EXPLANATION for (A). If both (A) and (R ) are correct but (R ) is not the correct explanation for (A ) If both (A) and (R ) are incorrect. If both (A) and (R ) are incorrect. Answer :D

Discussion

87962.	A proton is moving with kinetic energy 5xx10^(-27). What is the wavelength of de Broglie wave associated with it? ("Mass of proton"=1.66xx10^(-27) kg, h=6.6xx10^(-34) Js)
Answer» SOLUTION :`1.619xx10^(-7)`

Discussion

87963.	A Protein that controls the metabolism of glucose is
Answer» Oxytocin Insulin Haemoglobin Keratin Answer :B

Discussion

87964.	(A): Proteins are made up of a -amino acids (R) : During denaturation, secondary and tertiary structures of proteins are destroyed.
Answer» Both A & R are true, R is the correct EXPLANATION of A Both A & R are true, R is not correct explanation of A A is true, R is false A is false, R is true Answer :C

Discussion

87965.	A proposed mechanism for the catalysed decomposition of aqueous H_2O_2isH_2O_2 + I^(-) overset(k_1)(to) H_2O+ IO^(-) H_2O_2 + IO^(-) overset(k_2)(to) H_2O + O_2 + I^(-)where k_2 gt gt k_1 . Derive the rate law for the reaction.
Answer» SOLUTION :`- (d[H_2O_2])/(DT) = k_1[H_2O_2][I^(-)]`

Discussion

87966.	(A) : Propionaldehyde undergoes aldolcondensation . (R) :Propionaldehyde contains five alphahydrogen atoms
Answer» Both A & R are TRUE, R is the correct EXPLANATION of A Both A & R are true, R is not correct explanation of A A is true, R is FALSE A is false, R is true ANSWER :C

Discussion

87967.	A : Propene reacts with HBr in presence of H_(2)O_(2) gives 2-bromopropane as a major product. R : This reaction proceeds always through 2^(@) free radical as intermediate.
Answer» If both Assertion & REASON are TRUE and the reason is the correct explanation of the assertion, then mark (1). If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2) if Assertion is true STATEMENT but Reason is false, then mark (3) If both Assertion and Reason are false statements, then mark (4) Answer :3

Discussion

87968.	(A) Propeneandcyclopropane both giveadditionreactions only .(R ) propane and cyclopropane are chain isomer.
Answer» if both(A) and (R ) are correct and ( R) is THECORRECT explanationof the(A) ifboth(A) and (R ) are correct but ( R) is not thecorrectexplanationof the(A) if (A) is correct but ( R) is INCORRECT is (A)in incorrect but( R)is correct Answer :B

Discussion

87969.	A process that uses micro-organisms to convert harmful industrial wastes to less toxic or non-toxic compounds is
Answer» COMPLEMENT FIXATION Precipitation Bioremediation Bioconversion Answer :C

Discussion

87970.	A process that involves the union of two or more molecules to form a new molecular aggregate without losing any simple molecule is known as:
Answer» Polarisation polymerisation Photosensitization None Answer :B

Discussion

87971.	A process of heating the ore in absenceof air is called
Answer» roasting leaching liquation calcination Answer :A::C::D

Discussion

87972.	A process of making NH_3 is presence of a catalyst is called
Answer» synthesis gasification destructive distillation catalytíc decomposition Answer :A

Discussion

87973.	A process for making ammonia at high temperature and pressure in the presence of a catalyst is known as:
Answer» DESTRUCTIVE distillation Fractional crystallization Gasification Habers Process Answer :D

Discussion

87974.	A process employed for the concentration of sulphide ore is :
Answer» FROTH floatation Roasting ELECTROLYSIS Bessemerisation Answer :A

Discussion

87975.	Why is the froth floatation method selected for the concentration of sulphide ores?
Answer» FROTH floatation Roasting ELECTROLYSIS Bessemerisation Answer :A

Discussion

87976.	A primary amine, RNH_(2) can be reacted with CH_(3)-X to get secondary amine, R-NHCH_(3) but the only disadvantage is that 3^(@)amine and quaternary ammonium salts are also obtained as side products. Can you suggest a method where RNH_(2) forms only 2^(@) amine ?
Answer» Solution :This can be ACHIEVED with the helpof CARBYLAMINE REACTION. `"" RNH_(2) overset(KOH//CHCl_(3))(rarr) RNC overset(H_(2)//Pd)(rarr)RNHCH_(3)`

Discussion

87977.	a process A rarr D is difficult to occur directly instead it takes place in three successive steps, DeltaS(ArarrB)=40 e.u., DeltaS(BrarrC)=30 e.u., DeltaS(DrarrC)=20 e.u. where e.u. is entropy unit then the entropy change DeltaS for the process (ArarrD) is
Answer» + 90 e.u. + 50 e.u. -90 e.u. - 50 e.u. ANSWER :B

Discussion

87978.	A principal shell having the highest energy subshell to be 'g'can accomodate electrons to a maximum of .
Answer» 18 32 25 50 Solution :For .G. subshell , l = 4 . Theminimum value of principal QUANTUM numbern = 5 . No. oforbitals in5th shell `5^(2) = 25` , No . Of ELECTRONS `2 n^(2) = 2 xx 25 = 50`

Discussion

87979.	A primary amine, RNH_(2) can be reacted with CH_(3)-X to get secondary amine, R-NHCH_(3) but the only disadvantage is that 3^(@) amine and quaternary ammonium salts are also obtained as side products. Can you suggest a method where RNH_(2) forms only 2^(@) amines?
Answer» Solution :`1^(@)` Amines REACT with `CHCl_(3)` in presence of alcoholic KOH to form isocyanides which UPON catalytic reduction give `2^(@)` amines. `underset(1^(@)" Amine")(RNH_(2)) underset(("Carbylamine reaction"))OVERSET(KOH//CHCl_(3))to R-overset(to)(=)C underset(("Catalytic reduction"))overset(H_(2)//Pt)to underset(2^(@)" amine")(R-NH-CH_(3))`

Discussion

87980.	A primary amine reacts with benzene sulphonyl chloride to sulphonamide. The number of acidic hydrogens present is sulphonamide is
Answer» SOLUTION :

Discussion

87981.	A primary amine on reaction with alc. KOH and chloroform yields
Answer» ISOCYANIDE ALDEHYDE CYANIDE ALCOHOL ANSWER :A

Discussion

87982.	A primary amine is formed an amide by the treatment of bromine and alkali. The primary amine has
Answer» 1 carbon atom less than AMIDE 1 carbon atom more than amide 1 hydrogen atom less than amide 1 hydrogen atom more than amide Solution :`UNDERSET(("ACETAMIDE"))(CH_(3)CONH_(2)+Br_(2))+4KOHunderset(-2H_(2)O)rarrunderset(("Methyl amine"))(CH_(3)NH_(2)+2)KBr+2K_(2)CO_(3)`

Discussion

87983.	A primary amineis formedform amide, bromineand alkalie . The1^(0)amine has
Answer» onecarbonless thanamide ONE carbonmorethanamide one HYDROGEN LESS thanamide one hydrogen morethanamide ANSWER :A

Discussion

87984.	A primary amine heated with CS_2 in presence of excess of HgCl_2 gives isothiocyanate.The reaction is called :
Answer» HOFMANN's bromamide reaction Hofmann's mustard OIL reaction Perkin's CONDENSATION Hofmann's elimination Answer :B

Discussion

87985.	A primary amine can be converted into an alcohol by the action of:
Answer» `NAOH` `HONO` `NH_(4)OH` `HNO_(3) and HCL` Answer :B

Discussion

87986.	A: Primary aliphatic amines react with CS_(2) and HgCl_(2) give precipitate of Hgs. R: Secondary amine does not give precipitate of Hgs in this reaction.
Answer» If both ASSERTION & Reason are TRUE and the reason is the CORRECT explanation of the assertion, then mark (1). If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2) If Assertion is true statement but Reason is false, then mark (3) If both Assertion and Reason are false statements, then mark (4) Answer :2

Discussion

87987.	A primary alkyl halide would prefer to undergo :-
Answer» `S_(N^1)` reaction `S_(N^2)` reaction `PROP`-elimination racemisation Solution :Primary ALKYL HALIDES prefer to undergo `S_(N^2)` reaction.

Discussion

87988.	A primary alkyl halide would prefer to undergo ………. .
Answer» `S_(N)1` reaction `S_(N)2` reaction `alpha` - Elimination Racemisation Solution :DUE to less Steric hinderance, the incoming nucleophile will attack from opposite side of leaving GROUP RESULTING in inversion of configuration if a substrate is chiral.

Discussion

87989.	A primary alkyl halide would prefer to undergo____
Answer» `S_(N)1` reaction `S_(N)2` reaction `ALPHA`-Elimination Racemization Solution :PRIMARY alkyl halides prefer to undergo `S_(N)2` REACTIONS, i.e., (b) is correct.

Discussion

87990.	(A) Primary alcohols can be easily oxidised to aldehydes. (R) Aldehydes are prone to further oxidation to carboxylic acids.
Answer» If both (A) and (R) are CORRECT and (R) is the corect explanation of (A) If both (A) and (R) are correct but (R) is not correct explanation of (A) If (A) is correct but (R) is INCORRECT. If (A) is incorrect but (R) is correct ANSWER :D

Discussion

87991.	A primary alcohol on oxidation gives an____which on further oxidation gives a_______both containing the same number of carbon atoms.
Answer» SOLUTION :ALDEHYDE, CARBOXYLIC ACID

Discussion

87992.	A primary alcohol can be oxidised to an aldehyde by choosing the reagent-
Answer» `KMnO_4,HO^(o+)` `K_2Cr_2O_7,H^(o+)` `C_5H_5NH^(o+)CrO_3Cl^(o-)` `O_3` ANSWER :C

Discussion

87993.	A primary alcohol is a stronger acid than_____alcohol of the sae molecular formula.
Answer» SOLUTION :SECONDARY or TERTIARY

Discussion

87994.	A pressure cooker reduces cooking time because:
Answer» HEAT is more evenly distributed B.pt.of WATER INSIDE the COOKER is increased The high pressure tenderises the food All Answer :B

Discussion

87995.	A pressure cooker reduces cooking time because
Answer» heat is more UNIFORMLY distributed the PRESSURE tenderises the food the boiling point of WATER inside the cooker is elevated the boiling point of water inside the cooker is depressed. Answer :C

Discussion

87996.	In a pressure cooker the cooking is fast because
Answer» Heat is more evenly distributed The higher PRESSURE tenderizes the food The boiling POINT of water inside the COOKER is elevated The boiling point of water inside the cooker is depressed Answer :C

Discussion

87997.	A pressure cooker reduces cooking time because :
Answer» heat is more evenly distributed the HIGH pressure tenderises the food the BOILING point of WATER INSIDE the COOKER is elevated the boiling point of water inside the cooker is depressed. Answer :C

Discussion

87998.	A preservative is NOT capable of_________.
Answer» INHIBITING the PROCESS of fermentation arresting the process of acidification retarding the decomposition of food by microbes. increasing the nutritive VALUE of food ANSWER :D

Discussion

87999.	(A) Presence of electron withdrawing groups at p-position, increases the acidic strength of phenols(R) Presence of electron withdrawing groups at ortho and para position stabilises the phenoxide ion formed
Answer» Both (A) and (R) are TRUE and (R) is the correct EXPLANATION of (A) Both (A) and (R) are true and (R) is not the correct explanation of (A) (A) is true but (R) is FALSE Both (A) and (R) are false Answer :A

Discussion

88000.	(A) Presence of catalyst increases the rate of reaction (R ) Presence of catalyst increases the enthalpy of reaction
Answer» Both (A) and (R ) are true and (R ) is the CORRECT EXPLANATION of (A) Both (A) and (R ) are true and (R ) is not the correct explanation of (A) (A) is true but (R ) is false Both (A) and (R ) are false Answer :D

Discussion

Explore topic-wise InterviewSolutions in .

A qha-regia is a mixtue of

A purple coloured solution is made alkaline with KOH and is treated with KI forming potassium iodate. The same solution is acidified with H_(2) SO_(4) and again it is treated with Kl. However this time instead of potassium iodate, iodine gas is released. The purple coloured solution is of

A pure substance which contains only one type of atoms is called:

A pure substance can only be:

A: Pure silver is obtained by electrolysis of AgNO_3 solution R: In electrolysis impure silver is taken as cathode and pure silver is taken as anode.

A pure sample of 2-chlorobutane shows rotation of PPL by 30º in standard conditions. When above sample is made impure by mixing its opposite form, so that the composition of the mixture become 87.5% d-form and 12.5% l-form, then what will be the observed rotation for the mixture.

A pure dextrorodtory monocarboxyhe acid is treated with racemic mixture of an alcohol contaning one chiral carbon. The ester formed will be

A Pt complex of NH3 and chlorine produces four ions per molecule in the solution is :-

(A) Pure chloroform does not give precipitate with AgNO_3 solution. (R) CHCI_3 is covalent compound.

A Pt complex of ammonia and chlorine produces four ions per molecule in the solution is

(A) Protons are better projectiles than neutrons. (R ) The neutrons being neutral do not experience repulsion from positively charged nucleus.

A proton is moving with kinetic energy 5xx10^(-27). What is the wavelength of de Broglie wave associated with it? ("Mass of proton"=1.66xx10^(-27) kg, h=6.6xx10^(-34) Js)

A Protein that controls the metabolism of glucose is

(A): Proteins are made up of a -amino acids (R) : During denaturation, secondary and tertiary structures of proteins are destroyed.

A proposed mechanism for the catalysed decomposition of aqueous H_2O_2isH_2O_2 + I^(-) overset(k_1)(to) H_2O+ IO^(-) H_2O_2 + IO^(-) overset(k_2)(to) H_2O + O_2 + I^(-)where k_2 gt gt k_1 . Derive the rate law for the reaction.

(A) : Propionaldehyde undergoes aldolcondensation . (R) :Propionaldehyde contains five alphahydrogen atoms

A : Propene reacts with HBr in presence of H_(2)O_(2) gives 2-bromopropane as a major product. R : This reaction proceeds always through 2^(@) free radical as intermediate.

(A) Propeneandcyclopropane both giveadditionreactions only .(R ) propane and cyclopropane are chain isomer.

A process that uses micro-organisms to convert harmful industrial wastes to less toxic or non-toxic compounds is

A process that involves the union of two or more molecules to form a new molecular aggregate without losing any simple molecule is known as:

A process of heating the ore in absenceof air is called

A process of making NH_3 is presence of a catalyst is called

A process for making ammonia at high temperature and pressure in the presence of a catalyst is known as:

A process employed for the concentration of sulphide ore is :

Why is the froth floatation method selected for the concentration of sulphide ores?

A primary amine, RNH_(2) can be reacted with CH_(3)-X to get secondary amine, R-NHCH_(3) but the only disadvantage is that 3^(@)amine and quaternary ammonium salts are also obtained as side products. Can you suggest a method where RNH_(2) forms only 2^(@) amine ?

a process A rarr D is difficult to occur directly instead it takes place in three successive steps, DeltaS(ArarrB)=40 e.u., DeltaS(BrarrC)=30 e.u., DeltaS(DrarrC)=20 e.u. where e.u. is entropy unit then the entropy change DeltaS for the process (ArarrD) is

A principal shell having the highest energy subshell to be 'g'can accomodate electrons to a maximum of .

A primary amine, RNH_(2) can be reacted with CH_(3)-X to get secondary amine, R-NHCH_(3) but the only disadvantage is that 3^(@) amine and quaternary ammonium salts are also obtained as side products. Can you suggest a method where RNH_(2) forms only 2^(@) amines?

A primary amine reacts with benzene sulphonyl chloride to sulphonamide. The number of acidic hydrogens present is sulphonamide is

A primary amine on reaction with alc. KOH and chloroform yields

A primary amine is formed an amide by the treatment of bromine and alkali. The primary amine has

A primary amineis formedform amide, bromineand alkalie . The1^(0)amine has

A primary amine heated with CS_2 in presence of excess of HgCl_2 gives isothiocyanate.The reaction is called :

A primary amine can be converted into an alcohol by the action of:

A: Primary aliphatic amines react with CS_(2) and HgCl_(2) give precipitate of Hgs. R: Secondary amine does not give precipitate of Hgs in this reaction.

A primary alkyl halide would prefer to undergo :-

A primary alkyl halide would prefer to undergo ………. .

A primary alkyl halide would prefer to undergo____

(A) Primary alcohols can be easily oxidised to aldehydes. (R) Aldehydes are prone to further oxidation to carboxylic acids.

A primary alcohol on oxidation gives an____which on further oxidation gives a_______both containing the same number of carbon atoms.

A primary alcohol can be oxidised to an aldehyde by choosing the reagent-

A primary alcohol is a stronger acid than_____alcohol of the sae molecular formula.

A pressure cooker reduces cooking time because:

A pressure cooker reduces cooking time because

In a pressure cooker the cooking is fast because

A pressure cooker reduces cooking time because :

A preservative is NOT capable of_________.

(A) Presence of electron withdrawing groups at p-position, increases the acidic strength of phenols(R) Presence of electron withdrawing groups at ortho and para position stabilises the phenoxide ion formed

(A) Presence of catalyst increases the rate of reaction (R ) Presence of catalyst increases the enthalpy of reaction

A primary alcohol on oxidation gives anwhich on further oxidation gives a___both containing the same number of carbon atoms.